ARC forbids explicit message send of 'release'; since iOS 6 even for dispatch_release() calls: stripping it out in those cases is required. Use iOS 6 version value instead of macro for comparisons because we might get compiled on an old OS that does not define a later.
AVAssetWriter –finishWriting is deprecated in iOS 6.0; switch over to the new -finishWritingWithCompletionHandler: for that version and up.
Added YUV camera support to non-A5 GPUs. Added full-range YUV for better color reproduction. Fixed a crashing issue with YUV code on the iPhone 4.
Merge pull request #758 from raphaelschaad/master

iOS 6.0 Compatibility
Fixed compiler macros for targeting iOS 6.0.
Add color, hue, saturation and luminosity blend modes.

With formulas based upon the PDF specification which matches Photoshop behaviour.
Linear burn blend filter
Merge branch 'refs/heads/originmaster'
Merge branch 'refs/heads/linearburn-origin'
Merge branch 'refs/heads/colorblends-origin'