mode-lambda - sprite-based 2D graphics engine

Try running...

racket -l mode-lambda/examples/one

NOTE:
XXX layer-camera branch is an attempt to clean up parameters

MAYBE:
- parents for localized rotation? (skeletal animation)
- rotation about a different origin
- make animated gif creator (add screenshots to GL)
- ensure that layers can be used effectively for minimap
- add something like pict-finders
- trim/reposition inside a sprite (could be used for "blowing up" something?)
- make effects compatible with retroarch (or just get a much better crt effect)
- support full retina resolution: https://developer.apple.com/library/mac/documentation/GraphicsAnimation/Conceptual/HighResolutionOSX/CapturingScreenContents/CapturingScreenContents.html#//apple_ref/doc/uid/TP40012302-CH10-SW33 [or not because we just scale anyways]

- better crt?
http://gamasutra.com/blogs/KylePittman/20150420/241442/CRT_Simulation_in_Super_Win_the_Game.php?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+GamasutraFeatureArticles+%28Gamasutra+Feature+Articles%29

- Look at GLium: https://github.com/tomaka/glium

- Use Persistent Mapping (requires 4.5): https://www.opengl.org/wiki/Buffer_Object#Persistent_mapping
- Use Bindless textures? https://www.opengl.org/wiki/Bindless_Texture