first half second.  I think the order of inserting effects into the audio path
has something to do with it, so I've reordered everything to be ready before
starting the next track.

In addition you shouldn't get huge volume jumps when crossfading rapidly and I've improved the memory
allocation lifetimes.

Unfortunately you still sometimes get a bit of high-volume at the beginning of the next track but I don't
think that is juk's fault.

CCBUG:161168

svn path=/trunk/KDE/kdemultimedia/juk/; revision=809464