CFA Agnostic Debayering

[gennyble]

I couldn't think of how one would use the CFA that we're given by one of the various raw decoders, but uh, I think I figured it out? It wasn't that hard I was just lost.

It really is just looking around the current pixel for the values we need and then getting them. Hardcoding in their positions will still be faster, I imagine, so maybe we check to see if we have one hardcoded before calling back to the works-for-everything.

Some testing to see speed differences would be fun, too!

(this would also allow us to operate on non-cfa-aligned raw crops, which could be nice)

[gennyble]

We have an impl of nearest neighbor now doing this! It's currently what's used in rawproc. I want to grab the really-very-fast bilinear from the old rawproc and port it to new rawproc. It was like, 400ms.