Various documentation fixes.
Make note in Cray docs about the gres=craynetwork variable needed for
proper functionality.
Make configure --enable-developer also set --enable-debug
Fix potential buffer overflow.

This isn't that big of an issue for 14.03, but 14.11 added more to this
string which could overflow the buffer since sprintf is used instead of
snprintf.  Using xstrfmtcat fixes the issue and is easier to read code.
Merge remote-tracking branch 'origin/slurm-14.03' into slurm-14.11

Conflicts:
	src/slurmctld/job_mgr.c
Merge remote-tracking branch 'origin/slurm-14.11'