Changed build.xml to utf-8; replaces svn dependencies with git; updated copyright; created classes in tests

Suppressed generated libraries from the archive: they should be generated from source or obtained from a release

- fixed problem with initialising databases with non prepared queries yet (this seems to have been working with mysql)
- moved the statement close() in the finally clause
- reinstated the instructions for creating a database with postgres (double quotes around names)
- fixed a (mundane) bug in registerServer which was using idprefix

Better qualified the current postgres limitations (work with existing databases).

More precisely:
- avoid considering directory whose name ends by .jar as jarfiles (thanks postgresql)
- avoid loading module-info.class as a class (thanks gson)
- avoid testing com.mysql and org.eclipse.jetty (the former complains that we load deprecated Driver)

Servlet API is a mess. There are various implementations (oracle, tomcat, glassfish) with incoherent numbers.
This one comes from Jetty and is supposed to be Oracle's with its original pom.
It is more advanced than the 6.0 that was here before (better types).