Fixing windows convergence via winrm

adding fixes for winrm: 1.)- adding winrm to gemspec, 2.) Correct install_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, 4.)adding reader attribute for config
Yeah. Good point. I'll add that and resubmit.