Ability to use MySQL or other DB Engines

Added command line handler, for -db_uri, to give users the ability to specifiy the uri that is passed to SQLAlchemy.

I am currently running on MySQL in a SmartOS Zone, and it is working well.

Had to fix some column definitions, I am unsure as to the effect that this has had on the SQLite driver, should be ok though (I believe it ignores lengths on varchar columns.