fixed signed/unsigned warning
fixed signed/unsigned warning

ThomasWalter/vigra,psteinb/vigra,hmeine/vigra,DaveRichmond-/vigra,psteinb/vigra,dstoe/vigra,cbecker/vigra,xiwei-zhang/vigra,martinsch/vigra,stuarteberg/vigra,hmeine/vigra,cha007/vigra,ThomasWalter/vigra,kod3r/vigra,capturePointer/vigra,mmuellner/vigra,kod3r/vigra,DaveRichmond-/vigra,timoMa/vigra,cha007/vigra,mmuellner/vigra,dstoe/vigra,cha007/vigra,capturePointer/vigra,cbecker/vigra,capturePointer/vigra,dagophil/vigra,funkey/vigra,timoMa/vigra,dstoe/vigra,cha007/vigra,dagophil/vigra,mmuellner/vigra,capturePointer/vigra,DaveRichmond-/vigra,kod3r/vigra,psteinb/vigra,xiwei-zhang/vigra,ThomasWalter/vigra,psteinb/vigra,xiwei-zhang/vigra,funkey/vigra,hmeine/vigra,stuarteberg/vigra,dstoe/vigra,stuarteberg/vigra,martinsch/vigra,hmeine/vigra,dagophil/vigra,funkey/vigra,cbecker/vigra,dagophil/vigra,xiwei-zhang/vigra,martinsch/vigra,funkey/vigra,mmuellner/vigra,timoMa/vigra,stuarteberg/vigra,dstoe/vigra,hmeine/vigra,timoMa/vigra,dagophil/vigra,ThomasWalter/vigra,DaveRichmond-/vigra,funkey/vigra,martinsch/vigra,cha007/vigra,funkey/vigra,xiwei-zhang/vigra,cbecker/vigra,funkey/vigra,mmuellner/vigra,psteinb/vigra,timoMa/vigra,DaveRichmond-/vigra,ThomasWalter/vigra,kod3r/vigra,capturePointer/vigra,stuarteberg/vigra,martinsch/vigra,capturePointer/vigra,dagophil/vigra,ThomasWalter/vigra,psteinb/vigra,psteinb/vigra,kod3r/vigra,stuarteberg/vigra,martinsch/vigra,dagophil/vigra,hmeine/vigra,timoMa/vigra,cbecker/vigra,dstoe/vigra,cha007/vigra,timoMa/vigra,xiwei-zhang/vigra,capturePointer/vigra,cbecker/vigra,dstoe/vigra,ThomasWalter/vigra,DaveRichmond-/vigra,kod3r/vigra,kod3r/vigra,mmuellner/vigra,mmuellner/vigra,xiwei-zhang/vigra,stuarteberg/vigra,hmeine/vigra,cha007/vigra,DaveRichmond-/vigra