Issue/17

Alright, so this should be a reasonable long-term solution for our Raspberry Pi resolution problem.  This patch should enable natural change of pixel density.  I recommend starting the interface with "python main.py -m screen:nexus7.2", as I think this gives a pretty good pixel density on the Adafruit PiTFT.  The solution isn't quite perfect yet, there are slight issues with things like console fader spacing that I still haven't quite figured out.

Fixes #17