Not Cross-Platform

[bobpaul]

I'll work on a pull request for this, but I thought I'd open an issue if anyone has some discussion on this. Most of my computers are Linux, but I have access to a Mac

Changes needed:

• Eliminate dependence on Windows Registry from preferences.py
  My plan here is to use a .ini file for configuration on Mac/Linux. On Linux I can store to the standard XDG paths. I'll have to check if this works on Mac
• Eliminate dependence on Windows paths in filesysytem.py
  Ideally the paths would be detected somehow rather than just built from constants
• Determine why the GUI completely fails to load on Linux.
• Others?

With the first 2 complete, the CLI seems to work on Linux and should work on Mac.