Added FileManager and TopMenuModule

The TopMenuModule binds the buttons so that they open the sub menus: at the moment it also binds those events that don't have a proper place yet. FileManager contains all the functions that have something to do with files, that is loading, opening, saving and exporting.

js/Input.js

@@ -5,12 +5,7 @@ class Input {
 
         element.addEventListener(event,
         function (e) {
-            // e = event
-            //this = element clicked
-            functionCallback(e, ...args);
-            //if you need to access the event or this variable, you need to add them
-            //when you define the callback, but you cant use the word this, eg:
-            //on('click', menuButton, function (e, button) {});
+            functionCallback(...args, e);
         });
     }