More work on the multiplexer:

More work on the multiplexer:

o  Changed configuration of search servers and groups, added stand-alone
   declarations of groups, merging groups and the default route.
o  Search servers now have identifiers to avoid cluttering logs and
   parameters by hostnames and ports.
o  MUXSS can refer to a search server, group or merging group.
o  Bug fix in pinging.
o  mux -s now uses the screen width to list databases, not groups.
o  Added mux --testconfig, which also dumps all known route objects.