Store best score in localStorage

Dependency injection and hide best score for incompatible browsers

js/application.js

@@ -1,6 +1,6 @@
 document.addEventListener("DOMContentLoaded", function () {
   // Wait till the browser is ready to render the game (avoids glitches)
   window.requestAnimationFrame(function () {
-    var manager = new GameManager(4, KeyboardInputManager, HTMLActuator);
+    new GameManager(4, KeyboardInputManager, HTMLActuator, LocalScoreManager);
   });
 });