Yet another last minute UI change

With Deskbar-Applet 2.21.90 the often requested Button UI that was already part in 2.18 returned. When you use this UI the results will be attached to the panel. Nevertheless, the window UI is still the default one.

In addition, Deskbar-Applet now recognizes when you change your peferred browser and activates the appropriate modules for you. E.g. when you were using Web History and Web Bookmarks for Mozilla before changing the preferred browser to Epiphany, Web History and Web Bookmarks for Epiphany will be enabled and the Mozilla modules disabled.