Make the color conversions in dev_draw general for n-component colors.
Make the color conversions in dev_draw general for n-component colors.

Ignore-this: 17c173d23059e095e6264c668adfe274

darcs-hash:20100622192509-f546f-9ff18fb30501114316321f5381e4a9743c159d94.gz

nqv/mupdf,nqv/mupdf,nqv/mupdf,nqv/mupdf,nqv/mupdf,nqv/mupdf