* The per-experiment event scheduler now runs on ops instead of boss.
  Boss still runs elvind and uses events internally, but the user part
  of the event system has moved.

* Part of the guts of eventsys_control moved to new script, eventsys.proxy,
  which runs on ops and fires off the event scheduler. The only tricky part
  of this is that the scheduler runs as the user, but killing it has to be
  done as root since a different person might swap out the experiment. So,
  the proxy is a perl wrapper invoked from a root ssh from boss, which
  forks, writes the pid file into /var/run/emulab/evsched/$pid_$eid.pid,
  then flips to the user and execs the event scheduler (which is careful
  not to fork). Obviously, if the kill is done as root, the pid file has to
  be stored someplace the user is not allowed to write.

* The event scheduler has been rewritten to use Tim's C++ interface to the
  sshxmlrpc server on boss. Actually, I reorg'ed the scheduler so that it
  can ...