* Use KDirLister as suggested by dfaure to track changes to the folders we're watching.  This allows us to track deletion and refreshes in addition to additions.
* Shave about 20% off of the time needed to initialize the tree view mode.
* Correct my spacing errors in playlistbox.cpp
* Change the map used to hold the tree view text tags to a hash table, which should be faster as well.

It's all in one commit because I'm crappy at patch management. =D

svn path=/trunk/kdemultimedia/juk/; revision=342054