When publishing message, pass qos, clientId and messageId to ascoltatore.
When forwarding message, pass on qos and messageId to client.
When subscribing, pass qos to asoltatore.
Close ascoltatore when server is closed.
Tests for passing on qos and messageId.
Added test for QoS 0 messages and QoS 1 subscription.
Merge pull request #26 from davedoesdev/pass_options_to_backend

Pass QoS level to the backing MQTTAscoltatore in the tree scenario.
Bumped to version 0.5.0. Updated History.
Don't pass options to subscribe
Use original topic when finding qos of client
Cope with close event from client
Fixed test which was failing due to publishing after disconnect
Updated links to the documentation.
Added test to show why this change in mosca:

-    var qos = Math.min((options && options.qos) || 0,
-                       client.subscriptions[topic]);
+    var qos = Math.min(
+            (options && options.qos) || 0,
+            client.subscriptions[
+                    (sub_topic && sub_topic.replace("*", "#")) || topic] || 0);

and therefore this change in ascoltatori:

+      handler = null,
+      cb = null;
+
+    cb = function (pub_topic, payload, options) {
+      callback(pub_topic, payload, options, topic);
+    };

are necessary. Otherwise, subscriptions qos levels aren't retrieved correctly
(get from the topic in the message rather than the subscribed topic).
Added throughput measurement.
subscribe with closure around forward so we know the original topic
Fixed NPM script.

Closes #29.
Bumped to 0.4.1. Updated HISTORY.md.
Merge pull request #28 from davedoesdev/pass_options_to_backend

Don't pass options to subscribe
Bumped to v0.4.2 Updated History.
Bumped version to 0.4.2.