Fairly large overhaul of the JuK codebase to beat out a lot of the Qt 3 stuff.

Still a lot of Qt 3 code to go but at this point Q3ValueList, Q3Vector, Q3PtrDict and Q3Dict should all be gone.

In addition many loops have been foreach()'ed, which really does make it more readable.

There is a crash fix as well, now the polish() function in Playlist has been replaced with an initialization slot which is singleShot'ed since the timing of the polish event is apparently different than it was in Qt 3, which was making new Playlists crash when they were first shown.

Also I went through almost every header and pared it down to the minimum reasonably achievable, which required some additional headers in a few .cpp files but overall compilation time should be down and you won't have to rebuild all of JuK just because a header file got touched.

I haven't seen any regressions yet but then again I still can't play music either.