Convert from old platformer controls to runner-like setup

[pushfoo]

• [x] Remove TMX loading, or relegate it to a method
• [x] remove old style keyboard handling, one button jumping for now
• [x] scroll the blocks at the bottom
• [x] lock screen to max width
• [x] jump on space instead of up
• [x] disable window resize for now? alternatively, change camera zoom to match window size to keep constant scaling