Simple validation check for empty fossil collection number.
Fix old publication-related var names
Remove redundant form ID.
Add features to edit fossil collections

This includes reporting of related fossils, with these consequences:

 - Attempts to delete a collection that's assigned to 1 or more fossils will be blocked until the admin deletes those fossils or (more likely) re-assigns them to another collection.

 - When a collection's acronym is changed, the new acronym will be applied to any fossil that was using the old one.

Addresses #42.