Integrate the new "rephist" [rep(utation) hist(ory)] module to trace

Integrate the new "rephist" [rep(utation) hist(ory)] module to trace
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