o Minor features (development support):
    - Developers can now generate a call-graph for Tor using the
      "calltool" python program, which post-processes object dumps.  It
      should work okay on many Linux and OSX platforms, and might work
      elsewhere too.  To run this, install calltool from
      https://gitweb.torproject.org/user/nickm/calltool.git and run
      "make callgraph". Closes ticket 19307.