Lots of small optomization changes

Game has devmode draw onto Game.image so that screenshots now save the
devmode information.

ScreenshotManager renamed to Screenshot, removed from Render, takes a
BufferedImage instead of a pixel array. Game just sends its image
variable over.

GimbalImage renamed to BasicImage in preparation for imminent name
change, frame title also changed.

lots of commenting as always
Improved Keyboard memory usage

each control in keyboard is an array of bytes instead of shorts. AFAIK
it still matches all the keycode values provided by the KeyEvent class,
so it should be fine. I'm not sure if it matters whether the bytes are
signed or not. I hope it doesn't, will have to do proper testing at some
point.