Update graphics/libraw to 0.13.7.

Upstream changes:
* Changes in cropping code:
  o cropping is now works for Fuji files (instead of crash)
  o bad pixels map and dark frame subtraction is turned off if cropping enable
  o for technical reasons, coordinates of top-left corner of crop box are
rounded to multiple of 4 for Fuji files.
* ./configure stuff fixes:
  o install static libraries only when --enable-static is set
  o compiled samples are dynamically linked if shared library not disabled.
* OpenMP enabled for Visual Studio 2008 SP1+, but not for RTM

(gls)