[#591] Start work on TextureAtlas for WebGL batching
[#591] Start work on TextureAtlas for WebGL batching

- Precalculate the texture regions
- Added a new uvMap to each region for WebGL

TukekeSoft/melonJS,TukekeSoft/melonJS,TukekeSoft/melonJS,MarkoIvanetic/melonJS,melonjs/melonJS,melonjs/melonJS,gopalindians/melonJS,gopalindians/melonJS,srbala/melonJS,srbala/melonJS,rlugojr/melonJS,gopalindians/melonJS,rlugojr/melonJS,MarkoIvanetic/melonJS,srbala/melonJS,rlugojr/melonJS