Hoard 1.6.2

Stops edited links from sending you anywhere but the store.

• Links you can open (Open on Booth, Open download page, a creator's page) must now be https
  addresses on the item's own store, checked when data is read, when it's written, and in the pages. Before,
  any https address was accepted, so a program editing a record could point a button at a lookalike
  sign-in page. Downloads never came from stored links, and still don't.
• Data files (manifests, catalog.json, tags.json, asset.json and Hoard's library list) are sealed with a
  keyed signature. When something else edits one, the tools tell you, keep a copy, and don't use its links
  until the store is read again.
• New verify command in Hoard Downloader: checks every data file and rebuilds the catalog files.
• The catalog files are now format version 3 (docs/DATA-FORMATS.md). Using one download folder from two
  computers? Copy integrity.key between them (see the README).