Tor 0.0.2pre20 prerelease is out

[Roger Dingledine <arma@mit.edu>]

This release lays some groundwork for performance tweaking---the network
has been expanding lately and performance is starting to become, erm,
sporadic.

I've left my circuit-making debugging info in at log-level warn, so you
can play with it too and get a feel for when/how it breaks. Run it with
"-l info" if you want even more info.

pre20 should be compatible with pre18 and pre19. But I'd like to ask
at least all the servers to upgrade anyway, so I can start playing
with things.

http://freehaven.net/tor/dist/tor-0.0.2pre20.tar.gz

Note that 'make install' will clobber your torrc, so back it up if you've
changed it.

Improvements since 0.0.2pre19:

New features:
  - We now have a deb package, and it's in debian unstable. Go to
    it, apt-getters. :)
  - I've split the TotalBandwidth option into BandwidthRate (how many
    bytes per second you want to allow, long-term) and BandwidthBurst
    (how many bytes you will allow at once before the cap kicks in).
    This better token bucket approach lets you, say, set BandwidthRate
    to 10KB/s and BandwidthBurst to 10MB, allowing good performance
    while not exceeding your monthly bandwidth quota.
  - Push out a tls record's worth of data once you've got it, rather
    than waiting until you've read everything waiting to be read. This
    may improve performance by pipelining better. We'll see.
  - Add an AP_CONN_STATE_CONNECTING state, to allow streams to detach
    from failed circuits (if they haven't been connected yet) and attach
    to new ones.
  - Expire old streams that haven't managed to connect. Some day we'll
    have them reattach to new circuits instead.

Bugfixes:
  - Fix several memory leaks that were causing servers to become bloated
    after a while.
  - Fix a few very rare assert triggers. A few more remain.
  - Setuid to User _before_ complaining about running as root.