OxSqlJob: isAlreadyPresent implemented

new test OxSqlJobTest.java
new class EntityManagerProvider.java

SqlJob: some new methods declared
TargetJobContext: fianlizePerson and release have now an additional parameter SdiException
SDI-plugins-oxwall/pom.xml: Powermock added
CrudTestBase: mySession eliminated
OxProfileData.java implemented, incl. Testcase
Bugfix in TargetExecutor: calls to release and finalizePerson adapted
SdiException: new static method for converting an arbitrary Throwable into an SdiException