o Minor features (unit tests):
    - The unit tests now log all warning messages with the "BUG" flag.
      Previously, they only logged errors by default. This change will
      help us make our testing code more correct, and make sure that
      we only hit this code when we mean to. This is preparatory work
      for ticket 19999.
    - Our unit testing code that captures log messages no longer prevents
      them from being written out if the user asked for them (by passing
      --debug or --info or or --notice --warn to the "test" binary). This
      change will prevent us from missing unexpected log messages simply
      because we were looking for others. Related to ticket 19999.
    - Our link-handshake unit tests now check, that when invalid
      handshakes fail, they fail with the error messages we
      expected.

  o Minor bugfixes (unit tests):
    - The tor_tls_server_info_callback unit test no longer crashes when
      debug-level logging is turned on. Fixes bug 20041; bugfix on
      0.2.8.1-alpha.