Now fullscreen is a thing!

You can now set it to fullscreen by uncommenting the t.window.fullscreen
line in love.conf(). You can also press Esc to go back to the original
size and exit fullscreen, and press it twice to quit.
General list of additions:
* Fullscreen
* Quit through double-pressing Esc
* Reset size by single-pressing Esc
* Resize just by stretching the window.
* A bug in round 3 where some of the swaps would swap from offscreen.