Re-org the data handling.

Re-org the data handling.
- data is only written to the DB after all scripts are done.  This speeds up the client overall inside the critial code path and removes the requirements for DB semaphores to protect against multi-threaded writes.
- Moved to sqlalchemy instead of the bare mysql layer
- TODO add UI-layer methods back in for generating task summaries, etc.

git-svn-id: svn://svn.open-ils.org/ILS-Contrib/constrictor/trunk@789 6d9bc8c9-1ec2-4278-b937-99fde70a366f