[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] Improve TableIterator + Adapt ResultSetTableIterator (particularly because of the last commit about TAPType and VotType) + Add a TableIterator for VOTable input: VOTableIterator + Add its JUnit test case