clean/update todo

        . fix buffer unit test so it passes

Short-term:

        - add in 'notice' log level

        - make recommendedversions different for clients and servers.

        o add in 'notice' log level

        X make recommendedversions different for clients and servers.

          e.g. C0.0.3 vs S0.0.3?

        o put IP into the descriptor, so clients don't need to resolve things

        o when you hup, rewrite the router.desc file (and maybe others)

              points, and can look up circuits by location-hidden service

            o OPs send/handle BEGIN cells for location-hidden services

            o End-to-end communication for location-hidden services

        - a section in the man pages: how to configure hidden services

        o a section in the man pages: how to configure hidden services

        o let bob use himself as a rendezvous point

        o let bob choose himself as intro point

        o let bob replenish his intro points and republish

          num_failed circs, to prevent madness when we're offline (But

          don't count failed rend circs toward Bob's total, or Alice

          can bork him.)

        o deal with edge_type in connection_edge.c

        - retry end for certain reasons (resolvefailed, policyfailed)

        - preemptively build and start rendezvous circs

        - preemptively build n-1 hops of intro circs?

        - (n)ack introduction requests?

        - cannibalize general circs?

On-going

        . Better comments for functions!

        D Spec the stream_id stuff. Clarify that nobody on the backward

          stream should look at stream_id.

Cell:

        ACI (anonymous circuit identifier)    [2 bytes]

        Command                               [1 byte]

        Payload (padded with 0 bytes)         [509 bytes]

Relay payload:

        Relay command           [1 byte]

        Stream ID               [7 bytes]

        Partial SHA-1           [4 bytes]

        Length                  [2 bytes]

        Relay payload           [495 bytes]

For 0.0.2pre15:

        o don't pick exit nodes which will certainly reject all things.

        o don't pick nodes that the directory says are down