evproxy, which uses set_failover and set_connection_retries. The event
library had these as noops, so that was an easy change. Also, add back
in the async add/remove subscription stuff, which was already
implemented in pubsub but not hooked up from the event library.
In the tmcd/plab directory I purged all mention of elvin and changed it
to "event server". I also renamed the runelvin script to runevents.
In events/proxy I cleaned up the makefile and added evproxyplab to the
targets list since it should now build okay (no longer needs to link
against elvin stuff). Renamed elvindtest program to eventping, and
otherwise purged lots of "elvin" tokens.