make sure server gets close

lib/index.js

@@ -211,6 +211,9 @@ Server.prototype.attach = function(srv, opts){
       res.end();
     });
     srv.listen(port);
+
+    // Export http server
+    this.httpServer = srv;
   }
 
   // set engine.io path to `/socket.io`
@@ -328,6 +331,24 @@ Server.prototype.of = function(name, fn){
   return this.nsps[name];
 };
 
+/**
+ * Closes server connection
+ *
+ * @api public
+ */
+
+Server.prototype.close = function(){
+  this.nsps['/'].sockets.forEach(function(socket){
+    socket.onclose();
+  });
+
+  this.engine.close();
+
+  if(this.httpServer){
+    this.httpServer.close();
+  }
+};
+
 /**
  * Expose main namespace (/).
  */