The only thing we have to change is to self-close tags that don't
contain anything. This wasn't even an explicit change in standard. It
was already a rule, but I think it wasn't getting enforced very well
until a bugfix.
You can no longer open a whole stack of Prefs windows, or Create Torrent windows
Simplifies and fixes behavior when dropping files onto the app or the dock icon. Before, you could use drag-drop to create stacks of Create Torrent windows. Now, you can only create torrents from the home screen.
Fixes#665
