A Tool for Specification Archeology

* Show the spec.

* Allow the user to select a line and jump back to the version in
  which that line was last changed.

* For each version, show the N e-mails from the editor that were sent
  to the relevant lists immediately before or after the time of the
  checkin, link to IRC at that time, show the checkin comment, show
  bugs that were modified at that time.