Fix indentation issues in altTab.js, plus minor cleanup in some other files.

js/ui/genericDisplay.js

@@ -233,13 +233,13 @@ GenericDisplayItem.prototype = {
         return details;
     },
 
-    // Destoys the item.
+    // Destroys the item.
     destroy: function() {
       this.actor.destroy();
     },
-    
+
     //// Pure virtual public methods ////
-  
+
     // Performes an action associated with launching this item, such as opening a file or an application.
     launch: function() {
         throw new Error("Not implemented");