Work to ensure we can still run Usergrid WITHOUT Core Persistence.
More work to ensure tests still pass and things still work with old UG EntityManagerImpl and friends.
Merge branch 'two-dot-o' into corepersistence-off
Merge branch 'two-dot-o' into corepersistence-off

Conflicts:
	stack/core/src/main/java/org/apache/usergrid/corepersistence/CpEntityManager.java
	stack/core/src/main/resources/usergrid-core-context.xml
	stack/core/src/test/resources/log4j.properties
Restore Concurrent annotation, fix test failures.
Allow configuration of either old EM or new CP-based EM via a new "usergrid.persistence" property that can be set to either EM or CP.
remove unneeded log message.
Default should be CP in the two-dot-o branch.