Catch exception on server start

lib/server.js

@@ -216,6 +216,12 @@ function Server(opts, callback) {
         var server = interfaces.serverFactory(iface, fallback, that);
         that.servers.push(server);
         server.maxConnections = iface.maxConnections || 10000000;
+
+        // Catch listen errors
+        server.on('error', function (e) {
+          that.logger.error('Error starting Mosca Server');
+          that.emit('error', e);
+        });        
         server.listen(port, host, dn);
       }, done);
     },

test/server_error.js

@@ -0,0 +1,47 @@
+var steed = require("steed");
+
+var moscaSettings = function() {
+    return {
+        port: 1883
+    };
+};
+
+describe("mosca.Server.error", function() {
+    var instance;
+    var secondInstance;
+    var settings;
+
+    beforeEach(function(done) {
+        settings = moscaSettings();
+        settings.publishNewClient = false;
+        settings.publishClientDisconnect = false;
+        instance = new mosca.Server(settings, done);
+        this.instance = instance;
+        this.settings = settings;
+        secondInstance = null;
+
+    });
+
+    afterEach(function(done) {
+        var instances = [this.instance];
+
+        if (secondInstance) {
+            instances.push(secondInstance);
+        }
+
+        steed.each(instances, function(instance, cb) {
+            instance.close(cb);
+        }, function() {
+            setImmediate(done);
+        });
+    });
+    it("should get Error: listen EADDRINUSE :::1883", function(done) {
+        secondInstance = new mosca.Server(moscaSettings(), function(err, server) {
+            expect(server === secondInstance).to.be.true;
+        });
+        secondInstance.on('error', function(err) {
+            expect(err.toString()).to.be.equal("Error: listen EADDRINUSE :::1883");
+            done();
+        });
+    });
+});