This commit reverts commit 89418d13.

The reverted commit will be applied in another branch (probably 'adql-2.1') as
it is part of the next release of ADQL-Lib.

- Now, `ADQLParserFactory.createParser(...)` should be used to create a parser
- Only the new function `LOWER` is supported for the moment
- Not yet possible to manage the optional features _(next dev to come)_
=> 1st step for ADQL-Lib v2.0

- TAP adapted so that using the last stable version of the ADQL language
  (i.e. 2.0 for the moment)
  - but not yet possible to set the ADQL version to use in the configuration
    file

if the alias is not delimited in ADQL.

This commit fixes the GitHub issue #56

this table is declared with an alias. Instead, the table alias must be used.

Note: This problem occurred only when ADQLParser was used with a DBChecker.

This commit fixes the GitHub issue #53

sub-query. Without this information, it was impossible to resolve columns makingreference to sub-queries of the clause FROM. See the JUnit test case for a
concrete example.
(error raised by Hendrik Heinl - ARI/GAVO)