fix compiler warning: deprecated conversion from string constant to 'char*'
fix compiler warning: deprecated conversion from string constant to 'char*'

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