feat(manager): add destroy method

Author: JSteunou

README.md

@@ -122,6 +122,7 @@ Your manager has the following signature :
     on: Function,
     off: Function,
     get: Function, // get a specific joystick
+    destroy: Function,
     options: {
         zone: Element,
         multitouch: Boolean,
@@ -164,6 +165,14 @@ An helper to get an instance via its identifier.
 manager.get(0);
 ```
 
+#### `manager.destroy()`
+
+Gently remove all nipples from the DOM and unbind all events.
+
+```javascript
+manager.destroy();
+```
+
 ### nipple instance (joystick)
 
 Each joystick has the following signature :

src/manager.js

@@ -11,6 +11,7 @@ var Manager = function (options) {
     self.nipples.on = self.on.bind(self);
     self.nipples.off = self.off.bind(self);
     self.nipples.options = self.options;
+    self.nipples.destroy = self.destroy.bind(self);
     self.nipples.get = function (id) {
         for (var i = 0, max = self.nipples.length; i < max; i += 1) {
             if (self.nipples[i].identifier === id) {
@@ -270,3 +271,12 @@ Manager.prototype.processOnEnd = function (evt) {
     var index = self.nipples.indexOf(nipple);
     self.nipples.splice(index, 1);
 };
+
+// Cleanly destroy the manager
+Manager.prototype.destroy = function () {
+    this.off();
+    this.unbindEvt(this.options.zone, 'start');
+    this.nipples.forEach(function(nipple) {
+        nipple.destroy();
+    });
+}