hook_taxonomy_vocabulary_presave() is missing

Seems really straightforward ... I just took a quick test drive and everything seems in order.

One more review for good luck and we can probably mark this RTBC

Looks good.

I want to be really careful here with making API changes this late in the game (even if they are "harmless" additions), because it sends the totally wrong signal about API freeze, and we need to be focused on releasing Drupal 7, not adding more shiny.

On the other hand, looking at http://api.drupal.org/api/search/7/hook_taxonomy_ it definitely seems clear that this is a simple API omission, rather than a "new" feature. Additionally, since terms are entities, the lack of a presave hook for terms was in fact a bug with the conformance to the entity interface, and since vocabularies are also entities, this qualifies here as well.

Committed to HEAD. But please watch it with that "critical" status and only use it for issues that are actually critical and cause Drupal to cease to function.

Also, since this is an API change, it needs to be documented on the Module update page.

I think that's fine.