Changed api for listener instance. Transport is now listener property

Author: Josema

src/core/constructors/listener.js

@@ -4,7 +4,8 @@ dop.core.listener = function(args) {
     dop.util.emitter.call(this); //https://jsperf.com/inheritance-call-vs-object-assign
     args.unshift(dop, this);
     this.options = args[2];
-    this.transport = this.options.transport.apply(this, args);
+    this.transport = this.options.transport;
+    this.listener = this.options.transport.apply(this, args);
 };
 // Inherit emitter
 dop.util.merge(dop.core.listener.prototype, dop.util.emitter.prototype);