Modifies TD_Database getAllRevisionsOfDocumentID to have an additional paramter to
exclude deleted documents in the output.

When calling -getAllRevisionsOfDocumentID:anId onlyCurrent:YES excludeDeleted: YES,
one will get all conflicting revisions for a particular document.

This is used by CDTDatastore+Internal -activeRevisionsForDocumentId:(NSString*)

The tests in DatastoreConflicts were modified appropriately.