! - WIP: Levels just load a static image. Jittery.

x loading individual tiles, lags
No prior-processing, but heavy slowdown

x rendering maps on-the-go
heavy prior-processing, no slowdown

x try... loading a pre-processed image, just set up levels to load a
room-sized image file
Speeds things up, but not by enough. Still jitters.

- levels no longer make tiles
(but still initialize them)
~ load_level and make_tiles seperated in to their own methods