#3 Fix remhost to be more generic

[Victor Norman]

There is an application 'remhost' that currently
contacts the dmucs server and changes a host to be
'unavailable'. The host will not be sent any more
compilation tasks until it is administratively made
available again. You can actually copy 'remhost' to
'addhost' and run it, and that will change the host to
be available again.

This adminstrative tool should be generalized so that
it can send some different instructions to a running
dmucs server. E.g.:

o make a host unavailable / available.
o change the host's power index
o change the # of tasks that can be assigned to a host
(like changing its # of cpus, but a little different --
the # of cpus is used in calculating the load average
per cpu and we don't want ot change that).
o perhaps change the algorithm for computing what
affect the load average has on a host.
o other ideas?