added cannyEdgeImageWithThinning() version from gradient vector added documentation
added cannyEdgeImageWithThinning() version from gradient vector
added documentation

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