tor/changes/prop275-minimal

  o Minor features (future-proofing):

    - Tor no longer refuses to download microdescriptors or descriptors if
      they are listed as "published in the future".  This change will
      eventually allow us to stop listing meaningful "published" dates
      in microdescriptor consensuses, and thereby allow us to reduce the
      resources required to download consensus diffs by over 50%.
      Implements part of ticket 21642; implements part of proposal 275.