code: function checkPort(basePort, callback){
    return deasync(function(basePort, callback) {
      portfinder.basePort = basePort;
      portfinder.getPort(function (err, port) {
        callback(null, port);
      });
    })(basePort);
  }
docs: Returns the next open port
  @method checkPort
  @param  {Number} port to start checking from
  @return {Number} closest open port to one provided