Interface usability, code updates & improvements

1.1
- In the ignored file extensions and directories listboxes, a context
menu will now only show if an item is under the mouse. It will also
select the item it plans to remove before the menu shows up.
- Removed warning when adding multiple folders to the ignore list, and
one or more of them is already on the list.
- Removed and replaced legacy tray icon menu with MFC standard.
- Removed and replaced legacy folder dialog with MFC standard.
- Changed some NULL to nullptr.
- Changed some Wide functions to their original typedef.
- Changed some super class calls to __super.
- Fixed some integer warnings.
- Other code fixes.