renamed 'SPQuadEffect' to 'SPBaseEffect'

since it can be used for any triangle meshes, actually.
enhanced descriptions of abstract method exceptions
added missing import
added more convenience methods to SPVertexData'
added 'setPositionWithX:y:atIndex:' to SPVertexData
added missing appledoc task headers
added runtime-check that pooled objects are not used from multiple threads (only in DEBUG mode)
fixed check for state changes in quad batching

previously, quads with different blend mode did not cause a state change
Merge pull request #2 from arielsw/master

SPViewController will not initialize if "initWithCoder:" is called
fixed curly brackets
-Fixed bug when program populates list of uniforms