(merge with branch 'unknownFctType')

[TAP] Add an XML TableSet parser. The main modification done in JDBCConnection is about the schema prefix of table when the DBMS does not support schemas: now, only standard tables are expected with the prefix 'TAP_SCHEMA_' and the upload tables also with 'TAP_UPLOAD_'.

[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).

[TAP,ADQL] Improve and remake a part of the database connection. Missing javadoc has been added when missing in the modified tables.

[TAP] Replace Savot by STIL + Change datatype management in TAPColumn (vot-type is no more available from here), TAPType (no votable type inside it) and VotType (can now be created from a TAPType instance + a VotType instance can be converted easily in a TAPType object)

[TAP] Remove TAPTypes and create a new class to represent a TAP column type: TAPType. + Improve the conversion between VOTable type and TAP type by embedding it in TAPType. + Modify TAPColumn in order to integrate TAPType and that its VotType is just a conversion of a TAPType. {This commit is not compilable.}