NAT doesn't react if you delete a vocabulary... fatals when you create a node

Steps to recreate:

1) Create your taxonomy vocabulary and content type, and associate them with NAT.
2) delete your taxonomy vocabulary.
3) try to create a node in your content type.

You get fatal:

Notice: Trying to get property of non-object in taxonomy_term_save() (line 596 of /foobar/modules/taxonomy/taxonomy.module).
EntityMalformedException: Missing bundle property on entity of type taxonomy_term. in entity_extract_ids() (line 7501 of /foobar/includes/common.inc).

Backtrace shows that it's NAT trying to do it's thing, despite the vocabulary no longer existing. Visiting NAT's config page shows it still lists the old vocabulary, despite the vocabulary no longer existing.

NAT should probably test for vocabulary existence on the admin page and on node creation... or just hook into taxonomy term deletion to also delete the NAT setting.