ofxiOSVideoPlayer API updates

- replaced getPixelsRef() with getPixels()
- replaced getTexture() with getTexturePtr()
- introduced ofPixels and removed old `unsigned char` pixel arrays.
- replaced pixel order swizzling functions with vImage methods from Accelerate framework (same as in the OSX version of AV video player)
- updated ofxiOSVideoPlayer example with the API changes.
- added Accelerate.framework to iOS template project.
im just trying to test it but can't seem to make a call to `const ofPixels & getPixels() const;`
shouldn't the line below call that method?
`const ofPixels & pixels = video.getPixels();`