reserved word is encountered instead of a column/table/schema name/alias.

On the contrary to the previous commit, this time a list of SQL reserved words
has been added into the ADQL grammar. In this way, the parser will ensure that
no word of this list is used in an ADQL query. The raised error is then enriched
of an HINT message stating that this word is part of SQL, is not supported
by ADQL and must be written between double quotes if used as an identifier.

The list of SQL reserved words comes from the ADQL-2.0 standard, after removal
of all potentially used ADQL words, in order to avoid a conflict with the
already existing tokens in the ADQL grammar.

reserved word is encountered instead of a column/table/schema name/alias.

No list of ADQL reserved words has been added into the ADQL grammar.

However, the ADQL grammar has been slightly changed in order to provide a more
precise location of the REAL wrong part of the query.

Before this commit, if an ADQL reserved word (e.g. 'point') was encountered
outside of its normal syntax (e.g. 'point' no followed by an opening
parenthesis), the next token was highlighted instead of this one. Hence a
confusing error message.

For instance, the following ADQL query:

```sql
SELECT point
FROM aTable
```

returned the following error message:

> Encountered "FROM". Was expecting: "("

Now, it will return the following one:

> Encountered "point". Was expecting one of: "*" <QUANTIFIER> "TOP" [...]
> (HINT: "point" is a reserved ADQL word. To use it as a column/table/schema name/alias, write it between double quotes.)

This error message highlights exactly the source of the problem and even provide
to the user a clear explanation of why the query did not parse and how it could
be solved.

The idea is to get rid of special characters such as '-', '+' , '(', ...

This commit resolves a part of the Pull Request #14

and HashMap more generic by returning resp. a List and Map instead.

This commit resolves a part of the Pull Request #14

In the resulting SQL query, if there are an alias on the joined tables, these
aliases must be used in the ON clause (instead of the full table name).

For instance, the following ADQL query:

```sql
  SELECT *
  FROM tableA AS a NATURAL JOIN tableB AS b;
```

should be translated into the following SQL:

```sql
  SELECT *
  FROM tableA AS a
    INNER JOIN tableB AS b
      ON a.id = b.id
```

This commit complete the resolution of the Pull Request #16
(more details about the issue can be got in there)

In MS-SQLServer, the following functions return a value of the same
type as the given argument:
  - abs
  - ceiling
  - degrees
  - floor
  - radians
  - round.

Since ADQL requires that these functions return a DOUBLE
(i.e. a float in MS-SQLServer), it must be ensured that the given
argument is a float.

This commit partially fixes the Pull Request #16

when an incorrect character that can not be interpreted by
the JavaCC Token Manager is encountered.

Actually, the TokenMgrError thrown by JavaCC is caught by all
ADQLParser.parseQuery(...) functions, wrapped inside a ParseException
which is finally thrown instead of the TokenMgrError. In this way,
ADQL-Lib users just have to care about a single Throwable:
ParseException.

Besides the error message has been slightly modified from:

> Lexical error at line 1, column 10.  Encountered: "\u00e9" (233), after : \"\"

to:

> Incorrect character encountered at l.1, c.10: \"\\u00e9\" ('é'), after : \"\"

Thus, the error is more user-friendly, more easy to understand by users.
Additionally, the incorrect character is displayed, as before, in its unicode
expression, but also in its character form (instead of an integer value that
nobody can really understand).

This commit fixes the GitHub issue #17

The previous fix was made against the ObsCore-DM 1.1 because the given
IVO-ID was rejected by EuroVO registry. Now that EuroVO registry has
fixed its IVO-ID rule, the IVO-ID of ObsCore 1.1 is accepted.
Hence this commit.

On the contrary to other DBMS, MySQL supports schemas, but as databases.
Which means that JDBCConnection gets from the JDBC driver that MySQL does
not support schemas and so it tries to access TAP_SCHEMA tables with a
'TAP_SCHEMA_' prefix instead of 'TAP_SCHEMA.' one. Since MySQL does
behave like it supports schemas, JDBCConnection.supportsSchema must be
set to 'true' if the DBMS is MySQL.

Besides, since no schemas are returned by the JDBC driver
(cf DatabaseMetadata.listSchema(...)), the function
JDBCConnection.isSchemaExisting(String, DatabaseMetaData) must always assume
that the specified schema exists if the DBMS is MySQL. This is particularly
important when the existence of 'TAP_UPLOAD' must be checked, because if the
function returns 'false' the library will attempt to create the database/schema
'TAP_UPLOAD' and will obviously fail due to a lack of permissions. Of course,
it means that the TAP implementor must create manually the schema/database
'TAP_UPLOAD' him-/her-self.

The second particularity of MySQL is the quote character for identifiers.
It is a back-quote (`) instead of a double quote ("). To reflect this
difference, JDBCTranslator.appendIdentifier(...) has been overwritten in a new
JDBCTranslator extension: MySQLTranslator.

The translation of all SQL types and mathematical functions have been adapted to
MySQL according to the online documentation. Few tests have been done locally
with a tiny database. This seems to work but further testing should be
performed in order to ensure the stability of this implementation.

'result_'.

Additionally when an XML document is submitted in an HTTP POST request
(i.e. with the Content-Type = (text|application)/(.+-)?xml), this is
immediately set as a jobInfo in the created job.

This infinite loop occured only when the replacement object is just
a wrapping of the matching object ; after replacement, the new object was
inspected for matching objects.

Example: infinite loop if we want to wrap all foo(...) functions with
         the function ROUND in the following query:
    SELECT foo(foo(123)) FROM myTable
	     Expected result:
    SELECT ROUND(foo(ROUND(foo(123)))) FROM myTable
	     But generated result was:
    SELECT ROUND(ROUND(ROUND(......foo(foo(123))))) FROM myTable

See the test case TestDBChecker.testClauseADQLWithNameNull() for more details.

Now, it is recommended to throw a DBCancelledException from any DBConnection
long processing. It is already done for the upload of a table, the execution
of an ADQL query and the setting of a whole TAP_SCHEMA. The flag
JDBCConnection#cancelled has now a bit different meaning: it is set even if
the Statement.cancel() fails so that any JDBCConnection function can see that
a cancellation has been requested.

since the commit 8e2fa9ff.

(005fc622). The position of a TokenMgrError
was not there anymore.

(https://github.com/gmantele/taplib/commit/7a70c6038cef460ab169682bed391bb5ae1de1e9)

It was not possible to use a GROUP BY with a qualified column name.
So finally, now, a GROUP BY is a ClauseADQL<ADQLColumn> instead of
a ClauseADQL<ColumnReference>. Indeed, according to the ADQL's BNF,
GROUP BY items are only columns as they would appear in the SELECT
clause (i.e. qualified or not, delimited or not). On the other
hand an ORDER BY accepts ONLY column index or non-qualified column
name/alias.

The class ColumnReference is kept for backward compatibility (or in
case the next version of the ADQL grammar make items of GROUP BY and
ORDER BY of the same type: index or qualified column). Besides, this
class is still inherited for the ORDER BY clause items
(see adql.query.ADQLOrder).

a qualified column name should be allowed, but still no column index should be.

TAP capabilities resource content.

TAP capabilities resource content.

This error has been raised on the issue #32 by Zarquan.

- empty file
- not a valid VOTable document

In such cases, the following error message is returned:
  "The input file is not a valid VOTable document!"
A cause with more detais (especially the line and column numbers)
may be appended.

Cases handled with no error:

  - If the VOTable document has no rows, an empty table
    is uploaded. No error has to be returned.

  - If a row has a different number of columns than the number
    of declared FIELDs, additional values are ignored and missing
    values are replaced by NULL. This is actually nicely handled by
    STIL.

Two comments:

- JDBCConnection.getDBMSName(String url) is now deprecated ; it may disappear
  in a next version of the ADQLLibrary.
- In case the DBMS name can not be retrieved (generally because of an
  incomplete JDBC driver implementation), NULL will be returned.

Few useless casts have also been removed.

It is also now recommended to make DBConnection.executeQuery(ADQLQuery)
return NULL if the query has been aborted (indeed, the DBConnection is
the only one that can reliably know that fact). JDBCConnection has been
adapted consequently.

This class is using static attributes of type DecimalFormat.
Unfortunately this type of objects can NOT be accessed by multiple
threads simultaneously: it is not thread-safe. Parsing errors,
mostly during TAP uploads, have been experienced for this reason.

To solve quickly this issue, the main static public functions of
ISO8601Format have been synchronized.

apply a quick space replacement (by %20) for few URIs of the configuration file
and remove duplicated entry (encoding) from the Gradle build script.

A special test has also been added in getFile(...) in order to deliver
a clear error message for users using a former version with URIs in their
configuration file (only for file_root_path and metadata_file).

Two embedded DBMS are used: H2 and a little SQLite. JDBC drivers are provided
in the `lib` directory. The databases are created and deleted automatically
by the JUnit tests (see `test/tap/db_testtools/DBTools for more details`).

The ANT and Gradle build scripts have been updated to reflect all these test
modifications.

Two classes have been modified after compilation:
    - ADQLParser - a simple cast for one of the automatically generated
                   constructor.
    - ParseException - the token position has been stored for better
                       syntax error messages.
A note has been added at the top comment for both files to highlight
the modified parts and how to restore them after re-generation.