Change the commit call to when the DB is closed

Changed the commit call to when the database closed, as this speeds
operations considerably.
Python 3-erise fix_roms.py

Made the fix roms python 3 compatible.
Convert datfile_scan to lxml

Converted datfile scan to lxml as this appears to be more standard

Added the rebuild location to the command line.

Fixed a few python 3 bugs.

A bad commit, as 3 thigns, but I don't mind.