Color component order is inconsistent YCbCr between comments and code

[iger]

Description of PixelYCbCr type states that the color components are placed in Y Cr Cb order, which seems to reverse Cb and Cr as opposed to other pixel types that put them in the same order as listed in their name.
Looking at some of the code, the color components seem to be used as YCbCr in that order, not YCrCb as stated in documentation.

[Vincent Berthoux]

Thanks for the information, I've fixed the information.