system: initialize stderr on AVR
screen: Stub out blit array for AVR

The blit array is way too big (360 * 4 = 1440 bytes) and isn't being used
to render right now, anyway.
Revert "game: define game data as static global variable"

This reverts commit d66f06bded0784d22c5588b6835500429943db7e.

Found the problem... screen's blit array was too damn big.