Fix URL reversal fail for add_facility (no zone).
Basic code for doing deletion stubs locally.  Will not propagate remotely.
Removing is_deletable code.
Remove need for add_syncing_models
Introduce (debug) settings to allow deletions and viewing of deleted objects.
Introduce all_objects manager, which will always return deleted (and not-deleted) objects.
Work-around for validation issue on save, where deleted foreign keys can't be found (they're hidden!)
Don't update userlog info by default--otherwise, programmatic Django save-related stuff fails (or becomes really hard to do generically).
Missed removing a reference to `is_deletable`