o Minor bugfixes:
    - Stop trying to resolve our hostname so often (e.g. every time we
      think about doing a directory fetch). Now we reuse the cached
      answer in some cases. Fixes bugs 1992 (bugfix on 0.2.0.20-rc)
      and 2410 (bugfix on 0.1.2.2-alpha).

  o Minor features:
    - Make bridge relays check once a minute for whether their IP
      address has changed, rather than only every 15 minutes. Resolves
      bugs 1913 and 1992.