Add ability to create CC3Textures from existing Cocos2D CCTextures.

Add CC3Texture initWithCCTexture: & textureWithCCTexture: methods.
Extend CCTexture extension to support all CC3Texture2DContent behaviour.
CC3Texture now holds CCTexture, not CC3Texture2DContent.
CC3DemoMashUp textures the ground using a CC3Texture created from a CCTexture.
Move CCTexture extension from CC3CC2Extensions.h/m to CC3Texture.h/m.
CC3DemoMultiScene transitions between 3D scenes using Cocos2D transitions.

CC3DemoMultiScene transitions between 3D scenes using Cocos2D transitions,
without closing OpenGL in between.
Add CC3Backgrounder shouldRunTasksOnRequestingThread property to allow
backgrounding to be ignored and tasks run in foreground.
CC3DemoMashUp pauses during loading only when loading in background.
Remove use of special Cocos3D controller from CC3DemoMultiScene.
Ensure foreground GL context is established before creating background context.
Add CCNode asCCScene method to simplify wrapping CC3Layer in 2D scene.
Wrap CC3Scene onOpen in open and close 3D rendering.
Fix typo that ran sync thread tasks as async.
Remove use of deprecated CC3cene cc3Layer property from CC3DemoMashUp.

Add CC3DemoMashUpScene primaryCC3DemoMashUpLayer property and reference it
from CC3DemoMashUpLayer, instead of using deprecated CC3cene cc3Layer property.
Remove unused cocos2d-library search path from CC3DemoMashUp project.
Fix memory leaks.

Add release in CC3PVRTexture init when aborting & returning nil.
CC3NodeDrawingVisitor autorelease CCRenderer globalShaderUniforms.
CC3Layer release surfaceManager on dealloc.
CC3LayerRenderCommand release visitor on dealloc.
Remove extra retain in CC3SurfaceManager retainSurface:inIvar:.
CC3DemoMashUp don't load in background on Android.
Update support for Cocos2D 1.1.

Update support for Cocos2D 1.1.
Fix unnecessary scene reload when closing CC3DemoMashUp and CC3Performance scenes.
Update use of UIViewController in CC3Demo3DTiles.
CC3ModelSampleFactory now retains color & texture vertex content.
Update support for Cocos2D 2.1.

Use version-appropriate configuration for text alignment in CC3DemoMultiScene.
Update support for Cocos2D 3.0.

Fix compilation warning on log message format in CC3Texture.
Clean up template AppDelegates.

Use asCCScene to simplify wrapping CC3Layer in a CCScene.
Deprecate CC3NSViewController.
Support device camera backdrop with Cocos2D 3.1.
Support stencils and shadow volumes with Cocos2D 1.1.
Fixes to Retina & Android devices.

CC3Layer update content size correctly on Retina view size change.
CC3Layer remove color & opacity property declarations from interface.
CC3Demo3DTiles MainLayer content size correctly on view size change.
CC3DemoMultiScene IntroLayer content size correctly on view size change.
Pre-release testing.

Fix types in README.md.