shaders: add basic shaders for drawable shapes
WIP: shotshape: port to opengles-compatible calls
letter: comment leading character values
letter: use enumeration when drawing letters
WIP: letter: port to opengles-compatible calls
WIP: baseshape: port to opengles-compatible calls
WIP: normalbullet: port to opengles-compatible calls
WIP: smallbullet: port to opengles-compatible calls
WIP: movingturretbullet: port to opengles-compatible calls
WIP: destructivebullet: port to opengles-compatible calls
WIP: crystal: port to opengles-compatible calls
shaders: support variable buffer and vertex buffers
WIP: shield: port to opengles-compatible calls
WIP: ship: port to opengles-compatible calls
WIP: boat: port to opengles-compatible calls
WIP: shape: remove old display list-based code
WIP: bulletshape: all bullet shapes are now ported