Remove Skybox.pvr reference from CC3DemoMashUp project
Rename CC3BoundingBox to CC3Box. Rename related functions.
Merge CC3Texture and CC3GLTexture class hierarchies.

Merge CC3Texture and CC3GLTexture class hierarchies. Add ability to extract cocos2d
CCTexture2D instance from a CC3Texture.
Fixed NPOT texture not rendering.

Fixed NPOT texture not rendering. Fixed misleading error from CC3Mesh drawingMode
property when no vertex locations array in mesh. Fix OSX Xcode5 warning on casting
integer to pointer.
Fixed NPOT texture not rendering.
Fixes for more rigorous Xcode5 compilation error detection.
Merge with patches to primary repo.
Import user data from POD files.

Import user data from POD files into CC3PODNode userData and podUserDataSize properties.
Auto-free CC3Identifiable userData property on dealloc.  Add CC3Identifiable
sharedUserData property. Fix Xcode5 strict cast warning in PVRT code.
Shader selection improvements.

Add clearShaderProgram method to clear the shader program for a mesh node.
Add auto shader selection for CC3ClipSpaceNode. Rename CC3TexturableMaterial.vsh
file to CC3Texturable.vsh.
Refactor shader program classes and improve shader loading performance.

Refactor CC3ShaderProgram class to add CC3Shader classes to instantiate and cache
shaders to avoid loading same shader for each program. Rename CC3ShaderProgram class
to CC3ShaderProgram, which holds CC3VertexShader & CC3FragmentShader instances.
Rename several CC3GLProgram... classes and header files to CC3ShaderProgram....
Move shader GL calls to CC3OpenGL class. Stop using ccUseProgram() function to
track shader program state.