fixing string check in python 3.2
fixing string check in python 3.2

letolab/HTTPretty,andresriancho/HTTPretty,demianbrecht/HTTPretty,codepython/HTTPretty,gabrielfalcao/HTTPretty,xgess/HTTPretty,gabrielfalcao/HTTPretty,pxg/HTTPretty,demianbrecht/HTTPretty,paylogic/HTTPretty,xgess/HTTPretty,paylogic/HTTPretty,codepython/HTTPretty,xgess/HTTPretty,demianbrecht/HTTPretty,BenjamenMeyer/HTTPretty,pxg/HTTPretty,BenjamenMeyer/HTTPretty,paylogic/HTTPretty,pxg/HTTPretty,letolab/HTTPretty,Multiposting/HTTPretty,Multiposting/HTTPretty,andresriancho/HTTPretty,codepython/HTTPretty,letolab/HTTPretty,andresriancho/HTTPretty,BenjamenMeyer/HTTPretty,Multiposting/HTTPretty,andresriancho/HTTPretty