Provide an option to use native tooltips instead of the AWN style

Provide an AWN configuration checkbox to use native tooltips instead of the ones drawn by AWN. This could be placed inside the Themes -> Customize -> Tooltips area. Checking it on would gray out font/font color/background color, and of course, it would cause AWN to render the platform's tooltips. The rationale is that it gives a more consistent user experience when there are items in the notification area. Those items have native tooltips, and some users (e.g. me :-)) find it a bit jarring to see two tooltip styles when mousing over the panel.