refactor events handler so it can handle multiple args

lib/core/events.js

@@ -29,23 +29,26 @@ EventEmitter.prototype.setHandler = function(requestName, cb) {
   return _setHandler.call(this, requestName, cb);
 };
 
-EventEmitter.prototype.request = function(requestName, cb) {
+EventEmitter.prototype.request = function() {
+  let requestName = arguments[0];
+  let other_args = [].slice.call(arguments, 1);
+
   log("requesting: ", requestName);
   warnIfLegacy(requestName);
-  return this.emit('request:' + requestName, cb);
+  return this.emit('request:' + requestName, ...other_args);
 };
 
 EventEmitter.prototype.setCommandHandler = function(requestName, cb) {
   log("setting command handler for: ", requestName);
   return this.on('request:' + requestName, function(_cb) {
-    cb.call(this, _cb);
+    cb.call(this, ...arguments);
   });
 };
 
 EventEmitter.prototype.setCommandHandlerOnce = function(requestName, cb) {
   log("setting command handler for: ", requestName);
   return this.once('request:' + requestName, function(_cb) {
-    cb.call(this, _cb);
+    cb.call(this, ...arguments);
   });
 };