slurm_protocol_errno.h provides a default place for slurm specific error definitions until Jim completes his general errno implementation

Cleaned up comm layer , this never ends :)
added pack and unpack routines for new communcations paradigm

cleaned up packing and upacking for job_desc
added src/common/log.h include to resolve link warnings

lots of cleanup

Added a few extra helper funtions

inclusion of autoconf socket #ifdefs

changed variable type ssize_t in slurm_protocol_api.c to size_t
changed variable type ssize_t in slurm_protocol_api.h to size_t

fixed added set_slurm_addres_hton to slurm_protocol_util.c

had a return type of slurm_fd

slurm_protocol_api.c			contains the programers interface.
slurm_protocol_interface.h 		defines the lower layer interface.
slurm_protocol_pack.c			packs messages.
slurm_protocol_util.c			contains utility functions used by the protocol