bugfix
Merge pull request #986 from DrMoriarty/upstream

Trivial bugfix
Attempting to protect against improper deallocation of resources outside of the image processing OpenGL ES context.
Merge remote-tracking branch 'upstream/master'
Added Profile build configuration for optimized performance testing based on Release build
Added method to allow flipping between front and back facing cameras while also changing the capture session preset.
This is necessary when running with a preset that is too high a resolution for the front facing camera to handle, like AVCaptureSessionPreset1920x1080, for example.
Adding debug checking.
Merge branch 'master' of github.com:vhoto-dev/GPUImage