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
This method should raise an error if it can't make the URL available to the remote (since the run will fail).