[pkg] Replace custom "scripts" handling by a setuptools entry points http://setuptools.readthedocs.io/en/latest/setuptools.html#automatic-script-creation

Set a default value for arguments of cubicweb.cwctl:run() This will help making a console script entry point from this to get rid of the custom installation of scripts in setup.py. Accordingly, update all calls of this function.

[pkg] Drop custom install_lib command and use include_package_data instead The custom install_lib command appeared to be meant to install package data, as declared in __pkginfo__.py. Let's rely on setuptools' include_package_data[1] option to handle this. [1]: http://setuptools.readthedocs.io/en/latest/setuptools.html#including-data-files

[py3] Replace a unicode() occurrence in workflow views