[TAP] Remove all generic types + Delete specific (for ResultSet) output formatters + Modify the main output formatter

[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

[TAP] Add the interface TableIterator (whose implementations let iterate over any kind of table data set) and its first implementation for ResultSet + JUnit test case

Remove useless and blocking test (when url-pattern in web.xml is set to the root: /*) in the UWS URL parsing. + Add very basic check on its implementation

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).