Update Admin.js

Fix for longer forms, while removing unnecessary scroll from ajax modal-model dialogs.
Before:
![Before](http://jajus.com/Before.png)

After:
![After](http://jajus.com/After.png)

After (Long Form):
![After](http://jajus.com/After2.png)

Resources/public/Admin.js

@@ -64,7 +64,8 @@ var Admin = {
         });
         jQuery('.modal-body', modal).css({
             width:    'auto',
-            height:   '90%'
+            height:   '90%',
+            overflow: 'auto'
         });
     },
     setup_select2: function(subject) {