pmix: correctly split pmi messages

Thanks to @elenash for all the reviews
Merge pull request #245 from ggouaillardet/poc/pmi_slurm

pmix: correctly split pmi messages
dstore: remove unused variables
Per the PR and discussion on today's telecon, extend the process name definition as a two-field struct of uint32_t's down to the OPAL layer. This resolves issues created by prior commits that impacted both heterogeneous and SPARC support. This also simplifies the OMPI code base by removing the need for frequent memcpy's when transitioning between the OMPI/ORTE layers and OPAL.

We recognize that this means other users of OPAL will need to "wrap" the opal_process_name_t if they desire to abstract it in some fashion. This is regrettable, and we are looking at possible alternatives that might mitigate that requirement. Meantime, however, we have to put the needs of the OMPI community first, and are taking this step to restore hetero and SPARC support.
ORTE: undeprecate -x var=val in mpirun

mpirun -x var=val is back, actually it is useful alias for -mca mca_base_env_list "var=val"
btl/vader: fix a typo in mca_btl_vader_put_knem
Fix SLURM PMI2 component. set s2_nrank to the relative position of a process inside the node
(not relative position of a node inside the allocation).
mca base: fix trivial typos in help message
Merge pull request #267 from artpol84/s2_fix

Fix SLURM PMI2 component. set s2_nrank to the relative position of a pro...

Good catch!
Merge pull request #265 from miked-mellanox/topic/undeprecate_env_x

ORTE: undeprecate -x var=val in mpirun

Looks okay to me - thanks!
btl/vader: don't assume the address in the put/get segment is unmodified when
using knem

It is valid to modify the remote segment that will be used with the
btl put/get operations as long as the resulting address range falls in
the originally prepared segment. Vader should have been calculating the
offset of the remote address in the registered region. This commit
fixes this issue.
make cray pmi compile again

Commit @80f07b65 resulted in changes that
caused cray pmi component to no longer compile.
This commit fixes that issue.
better way to tell if a process is in a Cray PAGG

Use a more reliable way to tell if a process is
1) in a Cray PAGG
2) is actually considered an application process on
   a compute node (not for example, a process in a PAGG
   on a mom node).
PSM MTL: Don't connect procs already connected

PSM has issues when trying calling psm_ep_connect() more than once for a
specific peer.  Use the psm_ep_connect mask argument to avoid connecting
to processes that are already connected.

OMPI ticket #268.
oshmem/yoda: fix a typo in mca_spml_yoda_get_completion
fix missing copyright, no code change
configury: fix a typo
orte/util: add OPAL_{VPID,JOBID} types to orte_attr_{load,unload}
orted/pmix: fix pmix_server_release when several jobids are running on the same node
Fix C++ builds by removing no-longer-needed type declaration