Rawspeed kodak DCR and KDC support

Support for two Kodak raw formats:

  * DCR format used in the DCS Pro line. The files are actually 10bit raw generated by compressing 12bit with a curve. The reverse curve is embedded in the file and applied so this produces the exact same output as libraw.
  * KDC format used in the bridge camera line (e.g., P880) which turns out to be a simple 12bit packed format with weird but straightforward locations for the image offset and dimensions.

Tested against the "DCS Pro SLR/n" and "P880" files at rawsamples.ch.