python: colors.cxx: Added int8 type to a few function overload lists.
python: colors.cxx: Added int8 type to a few function overload lists.

cha007/vigra,dagophil/vigra,timoMa/vigra,capturePointer/vigra,mmuellner/vigra,capturePointer/vigra,cha007/vigra,capturePointer/vigra,timoMa/vigra,cha007/vigra,capturePointer/vigra,funkey/vigra,dagophil/vigra,ThomasWalter/vigra,dstoe/vigra,dstoe/vigra,cha007/vigra,dstoe/vigra,xiwei-zhang/vigra,mmuellner/vigra,ThomasWalter/vigra,timoMa/vigra,funkey/vigra,xiwei-zhang/vigra,capturePointer/vigra,dstoe/vigra,funkey/vigra,dstoe/vigra,mmuellner/vigra,mmuellner/vigra,cha007/vigra,cha007/vigra,dagophil/vigra,xiwei-zhang/vigra,timoMa/vigra,dstoe/vigra,capturePointer/vigra,dagophil/vigra,capturePointer/vigra,dagophil/vigra,funkey/vigra,xiwei-zhang/vigra,funkey/vigra,xiwei-zhang/vigra,ThomasWalter/vigra,timoMa/vigra,mmuellner/vigra,ThomasWalter/vigra,dagophil/vigra,timoMa/vigra,xiwei-zhang/vigra,mmuellner/vigra,ThomasWalter/vigra,xiwei-zhang/vigra,cha007/vigra,funkey/vigra,ThomasWalter/vigra,mmuellner/vigra,ThomasWalter/vigra,timoMa/vigra,dstoe/vigra,dagophil/vigra,funkey/vigra