Quickstart admin guide: describe file permission better

Directories created for executables, libraries, etc. have permissions
based upon the umask, which may not be desired.
Validate permissions of key directories at slurmctld startup

Report anything that is world writable.
Corrections to SUG13 agenda
Fix some possibly NULL pointers reported by CLANG

None of these have ever occurred, but these changes will harden Slurm
bug 403
Merge remote-tracking branch 'origin/slurm-2.6'
jobcomp/filetxt - Streamline the code

Eliminate extra variable and avoid changing the contents of a string
Minor refactoring of commit fa0af103d018d6dd783634cdfdc3ae3d5fc4632c
Default to CR_CPU if nothing is set other than select/linear
Move/Rename/Update confusing named function sched_param_type_string
to be select_type_param_string
Rename variable bitmap to node_bitmap

No change in logic, just rename a variable for greater clarity
Remove unneeded 'int main' in m4 script
select/cons_res: minor improvement in logging
Improve GRES support for CPU topology

Previous logic would pick CPUs then
reject jobs that can not match GRES to the allocated CPUs. New logic first
filters out CPUs that can not use the GRES, next picks CPUs for the job,
and finally picks the GRES that best match those CPUs.
bug 410
Fix for job requesting GRES on node that lacks any GRES

Previous logic would allocate job resources on such a node
rather than reject the job allocation on that node.
GRES fix for commit 6f50943cbcfe0d9c8155afe3aba0f07af1d3c022

For a system with hyperthreads and GRES bound to specific CPUs,
there was an error in assigning CPUs
Updated notes on what is wrong with the cray linking tests in the m4
script.
Add 'show licenses' option to scontrol command.
Dereference correctly the job_record from void **
Dereference pointers correctly for qsort()
Prevent uninitialized variable use

bug 403
Prevent possible zero divide

Not likely, but fixed problem reported by CLANG tool
bug 403