More docs and (way more!) testing needed.
Done:
- Authdirservers down directories from others.
- Generate and use running-routers lists
- Cache directories; store across reboots.
- Refactor directory parsing a bit; note potential trouble spots.
svn:r1985
successful/failed connections, successful/failed extends, and
connection uptimes.
It's still not done: more tests are needed, and not everything calls
connection/circuit_mark_for_close properly. This skews the results.
Also, there needs to be a 'testing' mode for non-OP ORs, where they
periodically build circuits just to test whether extends work.
svn:r1313
