two todo items we'll need for the blocking-resistance scheme

  - Design next-version protocol for directories

  - Design next-version protocol for connections

For blocking-resistance scheme:

  - allow ordinary-looking ssl for dir connections. need a new dirport

    for this, or can we handle both ssl and non-ssl, or should we

    entirely switch to ssl in certain cases?

  - need to figure out how to fetch status of a few servers from the BDA

    without fetching all statuses. A new URL to fetch I presume?

Deferred from 0.1.2.x:

  - Memory use improvements:

    - Look into pulling serverdescs off buffers as they arrive.