improved test performances for sq (reuse iConnection in DBUnits)

Conflicts:
	sonar-core/src/test/java/org/sonar/core/persistence/AbstractDaoTestCase.java
improved test performances for sq (reuse iConnection in DBUnits)
improved test performances for sq #2 (use sonar.jdbc.schema property to explicit schema for DBUnit)
improved test performances for sq #3 (use MetaDataHandler for MySQL)
Fixed backported imports
updated license header