Improve spring package scanning, fix test failures

Spring package scanning will no longer require a persistence.xml. Changed super.getEntityManagerFactoryBuilderOrNull(..) to  Bootstrap.getEntityManagerFactoryBuilder(..) since the latter searches for a default persistent unit which is unnecessary. if we want to use a persistence.xml, one should use the hibernate:ejb3 config instead.

Fix regression issues related to Issue #28 and autoincrement information.