added new classes to OF iOS project.

added,
- ofBufferObject
- ofFpsCounter
- ofThreadChannel
- ofTimer
Merge pull request #3349 from julapy/ios-new-classes

added new classes to OF iOS project.
ofxiOSVideoGrabber made compatible with new API

- replaced initGrabber() with setup()
- replaced getPixelsRef() with getPixels()
- replaced getDeviceList() with listDevices()
- added deprecation messages.
- general cleanup.
Merge pull request #3350 from julapy/ofxiOSVideoGrabber-api-update

ofxiOSVideoGrabber made compatible with new API
ofxiOSImagePicker update to work with new API.
Merge pull request #3351 from julapy/ofxiOSImagePicker-api-update

ofxiOSImagePicker update to work with new API.
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.
Merge pull request #3352 from julapy/ofxiOSVideoPlayer-api-updates

ofxiOSVideoPlayer API updates
ofvbo refactor wip

+ makes all utility methods pass through programmable attribute pipeline
+ makes sure all attributes are cleared when calling ofVBO::clear() - this wasn't the case for custom attributes
+ automatically assigns standard attributes to built-in pipeline when using utility methods or hand-setting attributes
+ unifies execution pathways by following the DRY principle
+ allows for 3d texture coordinates.
Fix for https://github.com/glfw/glfw/issues/222
cleanup
set VertexAttributeLocation (fixes programmable GL Renderer)
make sure to only activate custom attributes in fixed function renderer.
Merge pull request #3354 from procedural/glfw-missing-header-fix

Fix for https://github.com/glfw/glfw/issues/222
minor fixes in ofBufferObject

+ GL methods concentrated in ofBufferObject::Data to follow RAII idiom
fix non c++11 evaluation of shared_ptr
whitespace fixes
Merge pull request #3355 from tgfrerer/refactor-ofVbo

refactor ofVbo - ready to merge