Make it really works on VapourSynth R55+ (APIv4)
Also keeping backward compatibility with previous API. (not thoroughly tested though, report is welcome)
Depth, ToRGB, ToYUV, BM3D: support all options from fmtc.bitdepth
Depth, ToRGB, ToYUV, zDepth: remove option "prefer_props" as removed by latest core.resize