Add role management to the user management interface.
Oops, rollback models/api.rb in 50a7f8d8ea43d4d4c9a7a07d6a36d0e0da679995.

This history stuff wasn't ready to be committed yet and is part of something
else.
Add userstamping and change tracking on api users, admins, and apis.
Finally fix crazy duplicate breadcrumbs in the admin.

This is fixed by using a custom renderer rather than the normal. Although the
normal one should be fixed in a future version of crummy:
https://github.com/zachinglis/crummy/pull/49