Datasource dependent DAO and ConnectionProvider loading

New features:
-  Add datasource dependent DAO and ConnectionProvider loading
  - This allows to include DAOs and ConnectionProvider for different datasources in the same SOS which can be selected during the installation.
  - Corresponding to the selected datasource, the required DAOs and ConnectionProvider are loaded during the initialization.

Changes:
- Move some methods from Hibernate Datasource classes to abstract super classes
- Update PostgreSQL JDBC version to 9.3-1101-jdbc4
- Update PostGIS JDBC version to 2.1.3
- Update Hibernate version to 4.3.5.Final
  - Required adjustments to SessionFactoryProvider and UserType classes.