Comment 4 for bug 1398107

I have a working branch that I'd like some experienced eyeballs on:

https://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/csharp/lp1398107_alert_when_dying_bib_has_holds

I add a new overrideable event that alerts the user when they are deleting a bib record. Also, I think it's prudent to retarget any title holds to the destination bib when doing a volume transfer and the source bib runs out of volumes.