refresh library: delete broken links, re-read metadata information

Hi,

I have just started (yesterday) to use songbird and I must say it is on many ways a really great thing. But I do not find a couple of features which are for me knock-out creteria.
In short:

a way to keep the library up-to-date if you perform changes (file name/path or metadata) externally to songbird.

Those are the key "words":

1) How to completely delete the library data base and start over again with a scan from scratch (fundamental): in a clean way and without killing all other settings (say you radically change the structure of your music storage)
2) A "delete broken link" feature is missing (fundamental): say I rename/delete/move many files --> I will have the new ones found (if existing) with a scan (file -> import media) but the old ones will still be listed up, and being "many" a manual fix is a non sense.
3) A better solution for position 2. would be a refresh option for the entire database: not only for the files but also for the metadata information IN the files: say I keep the same file structure/names but I edit the metedata information with an external program. Songbird does not realize it and keeps the old information! (the metadata correction is fundamental too)
4) It would be obviously nice if the whole "refresh" procedure (scan for new songs, delete broken links, re-read and correct metadata information) would happen automatically at program start-up (nice to have but it would be enough for me if all those procedures could be started manually)

If there is already a way to do those things please tell me, if not please consider seriously to introduce those features soon in future releases while for sure a lot of people have the same demand.

thanks.