Ensure all 2D textures are loaded upright.

Ensure textures loaded by iOS & OSX are flipped upright during loading.
Change CC3Mesh populateAs... parametric population methods to create texture
coordinates assuming texture is upright. Change expectsVerticallyFlippedTextures
of CC3VertexTextureCoordinates and CC3NodesResource to default to NO.
Add environment reflection into standard GLSL shaders.

Add environment reflection into standard GLSL shaders. Consolidate common standard
vertex shaders into CC3TexturableMaterial.vsh.
Fix issue in cocos3d interaction with cocos2d GL state cache.
Fixes to texture sizing and cocos2d state management.

Fix incorrect setting of CC3GLTextureCube isFlippedVertically property. Fix texture
scaling for NPOT textures. Move semantic kCC3SemanticIsUsingLighting to node scope.
When moving from 3D to 2D, reset state of only those attribute arrays used by cocos2d.
Upgrade PowerVR library to version 3.1.
Add PVR cube-map support.

Add PVR cube-map support. Load PVR files using PVRT library.
Ensure both 2D & cube textures disabled & unbound for unused tex units.
Ensure tex unit 0 is active when leaving 3D.
Add CC3Node selectShaderPrograms method to select shaders during app startup.

Add CC3Node selectShaderPrograms method to select the shaders for each mesh node
during app startup, instead of selecting lazily. Add standard shader vars for bone
matrices in model space. Add animationFrameCount & animationFrameRate properties
to CC3PODResourceNode. Don't color individual vertices during node picking.
Track max number of texture units and vertex attribs used to avoid enabling/
disabling more than used. Clean up compilation errors in OSX release compile.
Merge branch 'master' of https://github.com/billhollings/cocos3d