in index lists AND in ranges.  Here is how negative numbers work in
ranges:

 If both numbers in a range are of the same sign (both positive, or both
 negative), then the range counts directly from the first number to the
 second number; it will not wrap around the "end" of the node list.

 If the numbers in a range differ in sign, the range wraps around the
 end of the list of nodes.

 Examples: Given a node allocation of foo[1-16]:

	-2-3  (negative 2 to positive 3) becomes foo[15-16,1-4]
	3--2  (positive 3 to negative 2) becomes foo[4,3,2,1,16,15]
	-3--2 becomes foo[14-15]
	-2--3 becomes foo[15,14]
	2-3   becomes foo[3-4]
	3-2   becomes foo[4,3]

only relevant to job allocations.

Add -T/--task-layout-byid which allows task layout by relative nodeid with the
  allocation.  For instance, given nodes foo[1-16] in an allocation, the command
  slaunch -T 1,[3-4],1,3,8,-1,0,-1 will run on tasks on nodes in the following
  order: foo[2,4-5,2,4,9,16,1,16]
  Notice that negative numbers are permitted.

Task layout by nodename is now -Y/--task-layout-byname.

The --relative option now allows a negative number.  -1 is the last node in
the allocation.

--task-layout and --task-layout-file options.

Also have the slurmstepd set the SLURMD_NODENAME env variable.

task distribution (but may fail if switch does not support arbitrary).

Update slaunch man page.
Add beginnings of salloc man page.

- SlurmdPidFile, SlurmdLogFile, and SlurmdSpoolDir may each contain a
  "%h" and/or a "%n", which will be replaced by the hostname or NodeName,
  respectively.
- Add new xstring.c xstrsubstitute() function.
- launch_tasks_response_msg_t structure now contains a task_ids array
- Remove SLURM_DIST_UNKNOWN from enum task_dist_states
- job_desc_msg_t now lists a seperate addresses for the 
  RESPONSE_RESOURCE_ALLOCATION message.
- Expand the job step context concept used previously for task "spawn"
  for poe.  The step context is now also used for nomal step launch.
  New SLURM API function slurm_step_launch() and associated support
  functions.
- Fix spaghetti header #includes relating to global_srun.[ch]
- Fix slurmctld segfault when slaunch --relative is used