made loading happen using libpng
remove unused AudioFile class
added async audio: also not working well
added zlib and libpng
use SDL_LockSurface instead of SDL_CreateImageFrom and mkdir before preloading assets
added a rotational drawing functionality to image that lets a user draw an entire image as being rotated and stretched
connect physics angle to object rotation
added the ability to save a set of drawing commands to a display list so it may be replayed later to be drawn
use proper coordinates for the level and wait until it is loaded before computing image offsets and widths