use snprintf() instead of sprintf()
Do not use stringstream for osx
Do not print help layer, bug#406
fixed compile error on newer C++11 compilers (g++48, clang33) that dont accept a cast to (char)NULL
Merge pull request #402 from alice23/master

fixed compile error on newer C++11 compilers (g++48, clang33) that don't accept a cast to (char)NULL
fixed sf.net bug #417 saving layer attributes
Merge branch 'master' of github.com:LibreCAD/LibreCAD