Unit test isolation

Unit tests for Jdbc feature store are not written to be launch in a random order. Some of them check data source state (for example after initialization) and others modify it. In result if a test that modify data source state is run before the one checking it's well initialization, the build will fail. A solution is to add @Transactional on tests to be sure that a rollback is perform on the database after. 
In addition, unit tests for ehcache feature store were getting a cache from CacheManager holding a singleton. So caches were not delete. A solution is to add an @After method to remove all caches.