KH - Fix segfault on song drop onto queue w/ no singer selected
KH - Fix queue not clearing when selected singer is deleted
KH - Regular singer dialog name editing now works

If you rename a regular who is already loaded, the singer's rotation
entry will NOT be modified, but queue changes will still be tracked
normally.  Next time the singer is loaded they will be loaded with the
new name.  I may, at some point, make regular renames change the
rotation as well, but am undecided at this point.