winrm fixes

adding fixes for winrm: 1.)- adding winrm to gemspec, 2.) Correct instal...l_msi_path to be powershell friendly, 3.) adding available and make_url_available_to_remote methods to winrm (make_url_available_to_remote is a noop since winrm cannot forward port but it raises an error when run locally), 4.)adding reader attribute for config 5.) fixing quote escaping for powershell to prevent variable expansion from breaking