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

Added a few extra helper funtions

added pad to slurm_addr type char pad[16 - sizeof ( int16_t ) - sizeof (uint16_t) - sizeof (uint32_t) ] ;
explictly defined IPPROTO_XXX in socket() call

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