Fix rgb() colour parser not to swap g and b.
Fix rgb() colour parser not to swap g and b.

svn path=/trunk/libcss/; revision=8696

prepare/netsurf_libcss,prepare/netsurf_libcss,prepare/netsurf_libcss,zhuyadong/libcss,zhuyadong/libcss,zhuyadong/libcss,servo/libcss,servo/libcss,servo/libcss