Trustline v0.2.0

Trustline now tells you when a newer version exists. At most once a day, it
asks the releases repository whether a newer release has been published, and
shows a notice if one has.

• The request sends nothing about you, your notes, or even the version you are
  running. It is a plain read of a public page, with no identifier of any kind
  attached to it.
• Nothing downloads or installs itself. The notice links to the release and the
  decision stays yours.
• Preferences → About turns the check off entirely, and reports a pending
  update whether or not you dismissed the notice.
• The last answer is remembered, so a pending notice does not vanish the moment
  you go offline — and a day on which the server could not be reached is retried
  on the next launch rather than counted as having been asked.

If you are running 0.1.0, this is the release you will not be told about: 0.1.0
has no update check. From here on, you will be.

Trustline v0.1.0

Add initial README for TrustLine App releases