Added slight buffering to UVCImageSource which fixes dropped frames due to races between the camera and processing threads.
Added slight buffering to UVCImageSource which fixes dropped frames due to races between the camera and processing threads.

godbyk/OSVR-Core,OSVR/OSVR-Core,OSVR/OSVR-Core,OSVR/OSVR-Core,godbyk/OSVR-Core,godbyk/OSVR-Core,OSVR/OSVR-Core,OSVR/OSVR-Core,godbyk/OSVR-Core,godbyk/OSVR-Core,godbyk/OSVR-Core,OSVR/OSVR-Core