Reset mods after every song.

This improves the experience a lot when the players are constantly
rotating.

Also change the default mods to 1.5x Overhead Cel.
Adding 3.5x and 4.5x mods.
Default to event mode with no menu timer.
Display the real time in the menu timer location.

This is kind of a hack; ideally there would be somewhere to put it
during gameplay, too.
Save a screenshot after every song.
Noteskin for couples mode.

I'm adding this even though I don't use it anymore, because I
want to be able to play well on arcade machines that don't have
a couples noteskin.  It's good for introducing players to couples
mode, though, so I think it's worth keeping.
Always display the song title in the evaluation screen.
Ignore pad input in menus, and ignore keyboard input in-game.
Add a PNG version of the icon for Linux launchers.
Make Crazy Loop the default song.
Adding gtk2 as a dependency so that the loading window gets built.