Ensures the deletions are wrapped in a transaction - for performance and to mitigate db corruption if one of the deletes fails.
Updates the PetaPocoRepositoryBase to ensure that the deletion process is wrapped in a transaction so if any of the processes fail, it all gets rolled back.
reverts PersistDeletedItem transaction because i forgot that the Commit() method of the UOW already takes care of the transaction.
Merge remote-tracking branch 'origin/6.1.4' into 7.0.0