clean up new dir spec a bit more

2. Router descriptors

   Router descriptors are as described in the current tor-spec.txt

   document.

   The router descriptor format is unchanged from tor-spec.txt.

   ORs SHOULD generate a new router descriptor whenever any of the

   following events have occurred:

      - A period of time (24 hrs by default) has passed since the last

      - A period of time (18 hrs by default) has passed since the last

        time a descriptor was generated.

      - A descriptor field other than bandwidth or uptime has changed.

      - Bandwidth has changed by more than +/- 50% from the last time a

        descriptor was generated, and at least a given interval of time (1

        hr by default) has passed since then.

        descriptor was generated, and at least a given interval of time

        (20 mins by default) has passed since then.

      - Uptime has been reset.

   After generating a descriptor, ORs upload it to every directory

   server they know.

   The router descriptor format is unchanged from tor-spec.txt.

3. Network status

   Directory servers generate, sign, and compress a network-status document