Decodes YUV 4:2:2 10-bit and RGB 12-bit files.
Older files with more subbands, skips, Bayer, alpha not supported.

Further fixes and refactorings by Anton Khirnov <anton@khirnov.net>,
Diego Biurrun <diego@biurrun.de>, Vittorio Giovara <vittorio.giovara@gmail.com>
Signed-off-by: Diego Biurrun <diego@biurrun.de>