Curator notes

Addresses https://trello.com/c/lzPFuTs3/262-urgent-notes-field-that-will-display-at-public-interface-and-allow-us-to-post-retraction-notice

If there is metadata in the dryad.curatorNote field, it will be displayed at the top of the Item Summary page.
That probably shouldn't be committed here, although it is pretty annoying overall :P