Local Transaction support sufficient for performance evaluation

Implement local transaction support such that it can be turned on by an environment variable (default off). Local transactions are those which run entirely in the client with no TM involvement. We expect this to improve performance over global/standard transactions. The initial implementation will be sufficient for evaluation by the Debit-Credit benchmark. Additional work will be needed to generalize the feature, particularly the escalation to global transactions. This will also not initially include single phase optimization as this is not needed for Debit-Credit.