Added that when a slurmctld closes the connection to the database it's registered host and port are removed.

added semi-support for cgywin systems.  The slurmctld doesn't work becuase it exports symbols to the dll's and dll'
s can't import things like that.  But things should compile correctly and user tools like sview appear to work corr
ectly.

OK, this will probably where this part of the project stops since I can't figure out how to have the dll's in windo
ws grab the symbols from the slurmctld (like part_list).  It just uses the private value which isn't what we want.
 Things like sview and such work fine though.  (In cygwin the slurmd gets the name in all uppercase so you have to define it that way)