don't traverse excluded folders to avoid PathTooLongException #156
don't traverse excluded folders to avoid PathTooLongException #156

pascalberger/docfx,hellosnow/docfx,LordZoltan/docfx,superyyrrzz/docfx,hellosnow/docfx,superyyrrzz/docfx,DuncanmaMSFT/docfx,LordZoltan/docfx,pascalberger/docfx,hellosnow/docfx,dotnet/docfx,DuncanmaMSFT/docfx,LordZoltan/docfx,pascalberger/docfx,928PJY/docfx,LordZoltan/docfx,superyyrrzz/docfx,928PJY/docfx,dotnet/docfx,928PJY/docfx,dotnet/docfx