layouts_update_layout(...) now enables to process an incoming buffer containing
a contiguous set of packed strings and push that information into a particular
layout. Only the entities key/value pairs are updated for now.

layouts_p_update_done is a new callback that will be triggered with an array of
entities pointers when an update is performed on a particular layout. This
callback will help layout plugins to perform various consistency checks and/or
update any internal states that should be updated based on the modified entities
information.

No information concerning the udated key/value pairs are provided for now.
For finer-grained controls over what has changed, the plugins will have to use
both the parse_entity callback and the update_done callback to handle what has
changed and what should be rebuilt after the update for now.

see 024c9fab036c8e6110b9276367dcf875a81876ef

> add a new 'operator' field in s_p_values_t

Provide the capability to manage key[+-*/]=val entries in the parsing logic.
A new operator field now enables to know which operation is associated to
a pair of key/value instead of the classical set. Introduced operators are
provided by the slurm_parser_operator_t type with the following value :

 * S_P_OPERATOR_ADD
 * S_P_OPERATOR_SUB
 * S_P_OPERATOR_MUL
 * S_P_OPERATOR_DIV
 * S_P_OPERATOR_MIN
 * S_P_OPERATOR_MAX
 * S_P_OPERATOR_AVG

It is the caller of the parsing logic that is responsible of using that
information in order to act as requested. The parsing logic do not do any
computation based on the extracted operator.

S_P_OPERATOR_{MIN,MAX,AVG} are internal operators not yet bound to particular
char in the parsing logic of 'key[operator]=val' entries. They are only used
for layouts internal logic.

Why:

Introducing the layouts framework, the parsing logic of SLURM was extended to
manage efficiently conf elements expansions. Layouts heavily rely on the SLURM
parser to tansform textual configurations into internal representations.

Looking at a way to provide live update of Layouts information, it was
interesting to reuse the parsing logic of SLURM instead of trying to do the
same thing somewhere else.

Introducing a "key[+-*/]=val" feature was thus mandatory in order to apply
numerical modifications of the layouts internal states on the controller side
instead of trying to compute that on the client side and then send the updated
information, loosing the capability to perform operations atomicallly.

> add S_P_{FLOAT,DOUBLE,LONG_DOUBLE} and related s_p_get_* functions

> enable true/false string parameter with S_P_BOOLEAN

Layouts logic was using true/false instead of yes/no|0/1|up/down
that were supported with S_P_BOOLEAN. Add true/false instead of reverting
to one of the already available parameters as it was strange to not have them.

> add "_." as valid characters in key names

> add s_p_parse_buffer to parse configuration lines from a Slurm Buffer

s_p_parse_file is a convenient way to handle the parsing of Slurm configuration
file. It however only works with traditional file and can not be used to process
a bunch of configuration strings.

s_p_parse_buffer provides the capability to parse a bunch of contiguous strings
packed into a Buf type, stopping the processing at the first unsuccessfull
string extraction from the buffer.

Add a stage 1.1 in the loading of the layouts in order to recover the updated
entities prior to building the relationships among them (stage 2) using the
states saved in Slurm state save location for the layouts to load.

Information concerning the relations among entities provided by the 'Enclosed'
conf pragma are not taken into account for now when reading from layouts state
files. No layout plugins callbacks are called when doing that for now.

Add a function to help packing a particular layout into a Buffer as a set of
strings terminated by a "\0" string and representing the current expanded
form of the layout configuration as it could be described in a standard conf
file.

Use that function to provide a state save logic generating expanded conf files
in the state save location, one file per generated layout. Entities not linked
to a particular layout at save state time will not be saved as considered as
no longer necessary.

Note that the tree structure of the layouts are also saved in the packed
information as well as in the generated expanded file.

Note: fix a bug when freeing layouts in slurm_layouts_fini along the way.

The layouts_keydef struct only stored the associated key name prefixed by
the type of layouts (or mgr) inorder to have a unique identification of
all the keydefs in the central hash table.

To help accessing the original key name as specified in the layout conf
file, the shortkey field now stores a copy of the original key. This is
a short increase in the memory footprint of the layouts_keydef struct but
as this structure is only allocated once per key in a layout, the global
overhead is very small but provides an efficient way to retrieve the key
name.

SPANK naming changes: For environment variables set using the
    spank_job_control_setenv() function, the values were available in the
    slurm_spank_job_prolog() and slurm_spank_job_epilog() functions using
    getenv where the name was given a prefix of "SPANK_". That prefix has
    been removed for consistency with the environment variables available in
    the Prolog and Epilog scripts.
bug 1570

No change in logic

Requests by normal user to reset a job priority (even to lower it) will
result in an error saying to change the job's nice value instead.

Conflicts:
	src/slurmctld/job_mgr.c
	src/slurmctld/job_scheduler.c

A non-administrator change to job priority will not be persistent except
for holding the job. User's wanting to change a job priority on a persistent
basis should reset it's "nice" value.
Without this change a user might lower a job's priority, but Slurm will
not lower it more based upon fair-share changes.

Increase the MAX_PACK_MEM_LEN define to avoid PMI2 failure when fencing
with large amount of ranks (to 1GB).

Verify that all plugin version numbers are identical to the component
attempting to load them. Without this verification, the plugin can reference
Slurm functions in the caller which differ (e.g. the underlying function's
arguments could have changed between Slurm versions).
NOTE: All plugins (except SPANK) must be built against the identical
version of Slurm in order to be used by any Slurm command or daemon. This
should eliminate some very difficult to diagnose problems due to use of old
plugins.

Bug 1469
Return values from void functions are unknown and were causing
list_for_each to short ciruit processing of the job list.

This validates that sbcast works on a job step allocation, which
is a subset of a job allocation.

This is a correction to patch 5a9277b1

This is a correction to patch 5a9277b1

Conflicts:
	doc/html/documentation.shtml

Fix for misleading job submit failure errors sent to users. Previous error
could indicate why specific nodes could not be used (e.g. too small memory)
when other nodes could be used, but were not for another reason.
bug 1537

Modify the command names per latest Cray documentation.
Add Cray API calls, which will replace the Cray command line
  interfaces when available. More work will be required for
  this conversion to the APIs.
Update documentation.

Correct the job array specification parser to accept brackets in job array
expression (e.g. "123_[4,7-9]").
This patch superseeds patch 8d811201
bug 1552

The logic fails if there are commas in the brackets:
slurmctld: job_str_signal: 3 invalid job id 1593_[2,5-6]
Updated patch in next commit
bug 1552

No change in logic. Just make error messages more uniform and complete

This takes the user to the home page rather than the download page.