* Added the new 'json_headers' template to shared.html
* Updated Database->get_anvils() to store 'anvils::anvil_uuid::<anvil_uuid>::query_time' to aid in JSON clients to know the data is coming from the server. Also fixed a bug where the normal 'modified_date' column wasn't being loaded from the database properly.
Signed-off-by: Digimer <digimer@alteeve.ca>