* Fixed issue causing Keyboard.justPressed to always fire (thanks stemkoski)

* Added Keyboard.addKey() which creates a new Phaser.Key object that can be polled for updates, pressed states, etc. See the 2 new examples showing use.

src/input/Key.js

@@ -0,0 +1,142 @@
+Phaser.Key = function (game, keycode) {
+
+	this.game = game;
+
+	/**
+	*
+	* @property isDown
+	* @type Boolean
+	**/
+	this.isDown = false;
+
+	/**
+	*
+	* @property isUp
+	* @type Boolean
+	**/
+	this.isUp = false;
+
+	/**
+	*
+	* @property altKey
+	* @type Boolean
+	**/
+	this.altKey = false;
+
+	/**
+	*
+	* @property ctrlKey
+	* @type Boolean
+	**/
+	this.ctrlKey = false;
+
+	/**
+	*
+	* @property shiftKey
+	* @type Boolean
+	**/
+	this.shiftKey = false;
+
+	/**
+	*
+	* @property timeDown
+	* @type Number
+	**/
+	this.timeDown = 0;
+
+	/**
+	*
+	* @property duration
+	* @type Number
+	**/
+	this.duration = 0;
+
+	/**
+	*
+	* @property timeUp
+	* @type Number
+	**/
+	this.timeUp = 0;
+
+	/**
+	*
+	* @property repeats
+	* @type Number
+	**/
+	this.repeats = 0;
+
+	this.keyCode = keycode;
+
+    this.onDown = new Phaser.Signal();
+    this.onUp = new Phaser.Signal();
+	
+};
+
+Phaser.Key.prototype = {
+
+	/**
+    *
+    * @method update
+    * @param {KeyboardEvent} event.
+    * @return {}
+    */
+    processKeyDown: function (event) {
+
+        this.altKey = event.altKey;
+        this.ctrlKey = event.ctrlKey;
+        this.shiftKey = event.shiftKey;
+
+        if (this.isDown)
+        {
+            //  Key was already held down, this must be a repeat rate based event
+            this.duration = event.timeStamp - this.timeDown;
+            this.repeats++;
+        }
+        else
+        {
+            this.isDown = true;
+            this.isUp = false;
+            this.timeDown = event.timeStamp;
+            this.duration = 0;
+            this.repeats = 0;
+
+            this.onDown.dispatch(this);
+        }
+
+    },
+
+    processKeyUp: function (event) {
+
+        this.isDown = false;
+        this.isUp = true;
+        this.timeUp = event.timeStamp;
+
+        this.onUp.dispatch(this);
+
+    },
+
+	/**
+    * @param {Number} [duration]
+    * @return {bool}
+    */
+    justPressed: function (duration) {
+
+        if (typeof duration === "undefined") { duration = 250; }
+
+        return (this.isDown && this.duration < duration);
+
+    },
+
+	/**
+    * @param {Number} [duration]
+    * @return {bool}
+    */
+    justReleased: function (duration) {
+
+        if (typeof duration === "undefined") { duration = 250; }
+
+        return (this.isDown == false && (this.game.time.now - this.timeUp < duration));
+
+    }
+
+};