Make halting on SIGINT async

This change gives adaptors/drivers more flexibility in halting. Additionally,
now, by default, all Adaptors/Drivers will remove all their event listeners
before halting, which should prevent some additional commands from being sent to
the adaptor during shutdown.

lib/adaptor.js

@@ -52,7 +52,11 @@ Adaptor.prototype.connect = function(callback) {
 
 // Public: Disconnects from the adaptor
 //
+// callback - function to run when the adaptor is disconnected
+//
 // Returns nothing
-Adaptor.prototype.disconnect = function() {
+Adaptor.prototype.disconnect = function(callback) {
   Logger.info("Disconnecting from adaptor '" + this.name + "'.");
+  this.removeAllListeners();
+  callback();
 };

lib/connection.js

@@ -84,8 +84,10 @@ Connection.prototype.connect = function(callback) {
 
 // Public: Disconnect the adaptor's connection
 //
+// callback - function to be triggered then the adaptor has disconnected
+//
 // Returns nothing
-Connection.prototype.disconnect = function() {
+Connection.prototype.disconnect = function(callback) {
   var msg = "Disconnecting from '" + this.name + "'";
 
   if (this.port != null) {
@@ -95,7 +97,7 @@ Connection.prototype.disconnect = function() {
   msg += ".";
 
   Logger.info(msg);
-  return this.adaptor.disconnect();
+  return this.adaptor.disconnect(callback);
 };
 
 // Public: sets up adaptor with @robot
@@ -111,8 +113,10 @@ Connection.prototype.initAdaptor = function(opts) {
 
 // Public: Halt the adaptor's connection
 //
+// callback - function to be triggered when the connection has halted
+//
 // Returns nothing
-Connection.prototype.halt = function() {
+Connection.prototype.halt = function(callback) {
   var msg = "Halting adaptor " + this.name;
 
   if (this.port != null) {
@@ -120,5 +124,5 @@ Connection.prototype.halt = function() {
   }
 
   Logger.info(msg);
-  return this.disconnect();
+  return this.disconnect(callback);
 };

lib/cylon.js

@@ -8,6 +8,8 @@
 
 "use strict";
 
+var Async = require('async');
+
 var API = require('./api'),
     Logger = require('./logger'),
     Robot = require('./robot'),
@@ -73,11 +75,21 @@ Cylon.start = function start() {
 
 // Public: Halts the API and the robots
 //
+// callback - callback to be triggered when Cylon is ready to shutdown
+//
 // Returns nothing
-Cylon.halt = function halt() {
+Cylon.halt = function halt(callback) {
+  // set a timeout, in case trying to shut everything down nicely doesn't work
+  Utils.after((1.5).seconds(), callback);
+
+  var fns = [];
+
   for (var bot in this.robots) {
-    this.robots[bot].halt();
+    var robot = this.robots[bot];
+    fns.push(robot.halt.bind(robot));
   }
+
+  Async.parallel(fns, callback);
 };
 
 if (process.platform === "win32") {
@@ -90,6 +102,7 @@ if (process.platform === "win32") {
 };
 
 process.on("SIGINT", function() {
-  Cylon.halt();
+  Cylon.halt(function() {
     process.kill(process.pid);
+  });
 });

lib/device.js

@@ -62,10 +62,12 @@ Device.prototype.start = function(callback) {
 
 // Public: Halt the device driver
 //
+// callback - function to trigger when the device has been halted
+//
 // Returns result of supplied callback
-Device.prototype.halt = function() {
+Device.prototype.halt = function(callback) {
   Logger.info("Halting device '" + this.name + "'.");
-  return this.driver.halt();
+  this.driver.halt(callback);
 };
 
 // Public: Expresses the Device in JSON format

lib/driver.js

@@ -52,7 +52,11 @@ Driver.prototype.start = function(callback) {
 
 // Public: Halts the driver
 //
+// callback - function to be triggered when the driver is halted
+//
 // Returns nothing
-Driver.prototype.halt = function() {
+Driver.prototype.halt = function(callback) {
   Logger.info("Driver " + this.name + " halted.");
+  this.removeAllListeners();
+  callback();
 };

lib/robot.js

@@ -275,15 +275,23 @@ Robot.prototype.startDevices = function(callback) {
 //
 // Halts the devices, disconnects the connections.
 //
+// callback - callback to be triggered when the Robot is stopped
+//
 // Returns nothing
-Robot.prototype.halt = function() {
+Robot.prototype.halt = function(callback) {
+  var fns = [];
+
   for (var d in this.devices) {
-    this.devices[d].halt();
+    var device = this.devices[d];
+    fns.push(device.halt.bind(device));
   }
 
   for (var c in this.connections) {
-    this.connections[c].halt();
+    var connection = this.connections[c];
+    fns.push(connection.halt.bind(connection));
   }
+
+  Async.parallel(fns, callback);
 };
 
 // Public: Initialize an adaptor and adds it to @robot.adaptors