This is the first set of patches aimed at improving the functions to convert between media types and various representations. Not everything ended up being necessary for what I wanted to do (MFVIDEOFORMAT seems to be the only format able to carry aperture information after all) but the tests and implementation are now there and will still be useful to convert media types from/to AM_MEDIA_TYPE formats.
-- v3: mfplat/mediatype: Implement MFInitAMMediaTypeFromMFMediaType for FORMAT_VideoInfo2. mfplat/tests: Add tests for MFInitMediaTypeFromVideoInfoHeader2. mfplat/mediatype: Implement MFInitMediaTypeFromVideoInfoHeader2. mfplat/mediatype: Implement implicit MFInitMediaTypeFromVideoInfoHeader subtype. mfplat/tests: Test each VIDEOINFOHEADER field conversion separately.