Speedups

Recently I optimized several parts of the SDK, mostly to be able to support a "bullet hell" type game (one of the ideas I'm kicking around.)

Here is a little summary of what I accomplished:

• Entities are much faster
• The heap is now faster and more memory efficient and lets you allocate up to 256MB 16MB (up from 1MB!)
• The Layer component was eliminated and folded into Entity so parenting is more efficient.
• Spritebatches were implemented; performance is not too shabby with 5000 moving sprites a frame on a 3.2ghz desktop.  It's definitely CPU bottlenecked; eventually I'll offload sprite rendering completely to the GPU via....
• The Shader module; shaders will bring huge performance gains without a doubt :P