Merge branch 'call_center' of https://github.com/QuickBlox/SDK-android into merge_from_call_center_to_dev

Conflicts:
	src/com/quickblox/module/videochat/core/objects/AudioRecorder.java
	src/com/quickblox/module/videochat/core/service/QBVideoChatService.java
	src/jp/co/cyberagent/android/gpuimage/VideoChatViewsLoader.java
	src/jp/co/cyberagent/android/gpuimage/renderers/CameraGlSurfaceViewRenderer.java
refactoring of videochat sample, putting changes from call_center branch
refactoring of videochat sample, putting changes from call_center branch