High FPS modes. SDL 2 example.

I have added support for QVGA capture at the following frame rates: 205, 187, 150, 137.  At 205 FPS, the video starts to get corrupted but at 187 FPS (and below) the video is good.

I have also added validation for FPS in the init method so that subsequent calls to GetFrameRate report the frame rate that will actually be used.

Last, I have updated the SDL example to SDL 2.  OpenGL rendering is used (where available) and the YUV format is handled internally by SDL.  Thus, yuv422rgba.h is no longer needed and I have removed it.