added asString() function for built-in types
added asString() function for built-in types

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