Don't allocate the SetDistributedTxnMessage or PrepareTxnMessage objects in AbstractTransaction unless we really need them...
Removed useless override of poll()
We can also allocate the FinishTaskMessage lazily in AbstractTransaction too...
We will now lazily create the read/write BitSets in AbstractTransction. The CatalogContext now includes a count on the number of tables
Merge branch 'anticache' of github.com:apavlo/h-store into anticache