Bug#1001525: ICC support should not be disabled in mupdf

[Gregory Heytings]

Package: mupdf
Version: 1.19.0+ds1-1

Debian has disabled ICC support in mupdf.  Because of this colors are not 
always rendered correctly.  In bug#952724 the "ICC support is not 
available" has been (almost) disabled.  Adding ICC support is easy:

git submodule add git://git.ghostscript.com/thirdparty-lcms2.git 
thirdparty/lcms2

and comment the FZ_ENABLE_ICC=0 and USE_SYSTEM_LCMS2=yes lines in 
debian/rules.