o Removed features
    - Remove the GiveGuardFlagTo_CVE_2011_2768_VulnerableRelays option;
      authorities needed to use it for a while to keep the network working
      as people upgraded to 0.2.1.31, 0.2.2.34, or 0.2.3.6-alpha, but that
      was six months ago.  As of now, it should no longer be needed or used.