the automatic datatype detection was missing for CENTROID functions.
--
Additionally, some JUnit test files of the `adql` package has been moved to
the correct location.

This is easily possible for concatenations, string constants and User Defined
Functions having a FunctionDef. A new special datatype was needed for
numeric functions and operations: UNKNOWN_NUMERIC. This special type
can not be set with FunctionDef.parse(...) and it behaves exactly like the type
UNKNOWN, except that DBType.isNumeric() returns true (as .isUnknown()).
Thus, while writing the metadata of a result in TAP, nothing changes:
an UNKNOWN_NUMERIC type will be processed similarly as an UNKNOWN type:
to use the type returned from the database ResultSet or to set VARCHAR.
(no modification of TAP was needed for that)

[ADQL,TAP] Add STC-S and UDFs support in the ADQL parser. Now, it is possible to provide a list of allowed UDFs, regions and coordinate systems. The ServiceConnection of TAP is now able to provide these lists and to propagate them to the ADQLExecutor. UDFs and allowed regions are now listed automatically in the /capabilities resource of TAP. The type 'geometry' is now fully supported in ADQL. That's why the new function 'isGeometry()' has been added to all ADQLOperand extensions. Now the DBChecker is also able to check roughly types of columns and UDFs (unknown when parsing syntactically a query). The syntax of STC-S regions (expressed in the REGION function) are now checked by DBChecker. However, for the moment, geometries are not serialized in STC-S in the output....but it should be possible in some way in the next commit(s).

ADQLObject has now a new function: getPosition(). To allow it, the parser and all ADQL query tree item have been modified to define this function properly. The parser is setting this position for all parsed items. The test class/main function "TestGetPositionInAllADQLObject" aims to check that after a parsing all items really have a defined position.

ADQL: Correct version number for all modified ADQL related classes since the official v1.1 release. Now, version number after any modification in ADQL is v1.2.

ADQL: Completely change/improve Joins management, and particularly NATURAL JOIN and USING JOIN. Now, every joined columns are represented by a DBCommonColumn instance which has a given table coverage.
Before, there was a problem while using at least 3 or 4 NATURAL JOINs. Bug raised by Menelaos Perdikeas (ESAC).