1) Use all ATF features that only require reading the UID at all times. GUI option now controls whether new UIDs are
written to files. Note that this helps generalize ATF; we can use this to now enable other writes to metadata if we
wish and have it be a global "yes you can touch my files" setting.
2) Only force a rescan/playlist clear the first time ATF is turned on (err, since this commit...)
3) If Amarok is closed before rescan finished, don't force it on restart...takes too long for some people.
4) ChangeLog updates.