TODO

* Implement render to texture. Rough plan: add Framebuffer.lua, an object 
  representing the framebuffer and its attachement points. Replace
  lib:render(cam, objs) by lib:render(cam, objs [, framebuffer]).

* Implement transform feedback.
* Transform has a (yet unused) notification mechanism. Use case
  was camera following object etc... Should we remove it and leave
  that to the client of the library ? 

* Camera, implement simple orientation facilities (lookat) .
* Buffer
** Switch to zero-based indexing RAPIDLY (before too much code gets
   written), it's too confusing when you implement algorithms.
** Add support so that Buffer can just wrap a malloced block of memory.

* Allow to bind keyed tables for uniforms, map them to GLSL structs. 
* Improve M4 documentation.
* Implement M2, M3. 
* Finish V3_test.lua (mostly done).
* Implement {V4,V2,M4,Color}_test.lua.
* Cleanup demos.
* Cleanup predefined geometry/effects.
* Make definitive shaders for Wireframe, Normals, Points, Lines, Bezier. 
* Implement better manipulators, orienters in 3D space.
* Implement RendererGLES.lua
* Implement cube map textures.
* grep TODO.