FPS now only displays in debug mode

-Used asserts (because pygame.display.set_caption returns None, and not None is True)
-When not in Debug, "Invasodado" is shown in the caption
Normalized the grid representation of blocks

-I.e. blocks are now references block[x][y] instead of block[row][col] (which was essentially block[y][x])
-Removed blockgrid._match_set and made it local to blockgrid.update()
-Made Block.GRAVITY and Block.MAX_SPEED fully global
Merge branch 'master' of https://github.com/CorundumGames/Invasodado

Conflicts:
	game/block.py