working sync-threadpool

* Completed mapping of async dbpool
* Fixed shared db initialization.

Stuff To Be Fixed yet:

[ ] All inserts have to be done from the sync threadpool.
    Right now we're reusing the connection from multiple
    threads in the syncer. I'm assuming the writes are automatically
    locking the file at the sqlite level, so this shouldn't pose a
    problem.
[ ] Correctly handle the multiprocessing pool, and the callback
    execution.