added preliminary line support to circular_buffer

Add support for daemonizing slurmctld with -d option.

DOWN node to stay that way even after registration.

fixed daemoninze fcntl include
added errcodes

Moved job and job step specific code out of controller.c into pack.c.
Also removed build of list code (for improved speed, this will be
a very commonly used RPC).

Also fix purge of defunct job steps.