[Enhancement] Make it usable with Python 3 too

[xNinjaRose]

This should be able to run with python 3 also not just 2, not everyone uses 2 since 3 has been mainstream for a long time now

[apocalyptech]

Ended up looking at this repo 'cause someone was asking me some questions about my fork, and noticed this issue. I realize this response is coming six months late, but my fork is Python 3-based now: https://github.com/apocalyptech/borderlands2/

(Note that the commandline arguments have changed a bit on my fork as well)