Document display option
Merge pull request #27 from Cheeseness/master

Tidies virtual GUI cursor image
Assert that the video subsystem is initalized on config load/save

(Just to prevent future errors. We do keycode-to-string conversions in
there, and it's very tempting to move config file loading to an
earlier point in the startup phase, even before SDL_Init.)
Add language option
Adds Octocat ball.
Use with permission dated 2013-11-12.