Switch optimized converter functions back to custom SSE2 memory copy.
Optimize and simplify SSE2 load/store
Move plane_copy to pixconv.cpp
Implement plane_copy_sse2, optimized plain copying of frames.
Update plane_copy to be the same as plane_copy_sse2 without the SSE2 copy.
biPlanes is documented to always be 1.
Remove unused function
Fix yuv422 -> yuyv/uyvy crash
Convert dstStride to ptrdiff_t
Convert frame stride to ptrdiff_t
DVD Subtitles: Really obey the DVD Composit event or the forced sub flag.
DVD Subtitles: Try to improve the handling of subtitles without proper timings.

Ensure the stop time is always checked and don't change the timings when they are unknown.
Properly timeout DVD subtitles when receiving a new one to prevent overlap.
Fix DVD subtitle overlap if a untimed subtitle replaces timed subs.
Update ffmpeg