non admins can't change observatory while admins can
Remove extra blank line
Restrict observation delete to admin users
Restrict observation create to admin users, users with matching default observatory
Require an observation to still have observatory_id on update
Restrict updates to admin, or users with matching default observatory
Do not allow updates after already published
Add Allow header to 405 response code, per spec
Make ObservationView show save/publish errors in modal dialog