Ogm 363 named native query

This patch will allow the user to use the annotation @NamedNativeQuery.

While working on it I've noticed that almost every method in SessionImpl is calling this function:  
```
private void checkTransactionSynchStatus() {
	pulseTransactionCoordinator();
	delayedAfterCompletion();
}
```

If I'm not wrong it is to warn the transaciton manger that the component is still doing something. We are not doing this in OgmSession currently, I think it would make sense to do the same when a backend support transactions.

What do you think? Should I open a JIRA?