  o Minor bugfixes:
    - On SIGHUP, do not clear out all TrackHostExits mappings, client DNS
      cache entries, and virtual address mappings: that's what NEWNYM is
      for.  Bugfix on Tor 0.1.0.1-rc; fixes bug 1345.
    - When TrackHostExits is changed from a controller, remove any
      mappings for hosts that should no longer have their exits tracked.
      Bugfix on Tor 0.1.0.1-rc.
    - When VirtualAddrNetwork option is changed from a controller,
      remove any mappings for hosts that were automapped to
      that network.  Bugfix on 0.1.1.19-rc.
    - When one of the AutomapHosts* options is changed from a
      controller, remove any mappings for hosts that should no longer be
      automapped.  Bugfix on 0.2.0.1-alpha.
