code: function popupLogin(params) {
  	switch(gui_type) {
  		case 'nw':
  			popupNWLogin(params);
  			break;
  		case 'nw13':
  			popupNW13Login(params);
  			break;
  		case 'electron':
  			popupElectronLogin(params);
  			break;
  		default:
  			throw new Error('The Twitch SDK was not initialized with any ' +
  			                'compatible GUI API.');
  			break;
  	}
  }
docs: Opens a login popup
  @private
  @method popupLogin
  @param {Array|Object} params