MaxMemPerNode, MaxMemPerCPU, DefMemPerNode, DefMemPerCPU

Used to pack/unpack new uint64_t arrays into older uint32_t
array format for RPCs.

Change RPCs and add encode/decode logic for past version.

Change variables and structures to uint64_t:
def_mem_per_cpu, max_mem_per_cpu, free_mem, real_memory, actual_real_mem,
job_mem_lim, step_mem_limit, pn_min_memory, job_mem.

Change MEM_PER_CPU flag to 64th bit instead of 32nd bit.

Note that additional work is required to address local variables.

Also need to add table conversion logic to MySQL, as mem_req column
needs to change type to 'bigint unsigned' from 'int unsigned'.

Copy previous format, but do not change yet. Update RPCs involving:
def_mem_per_cpu
max_mem_per_cpu
free_mem
real_memory
actual_real_mem
job_mem_lim

bug 3065

Add Slurm overview by Alex on first day, move KNL to second morning,
shift roadmap to right after lunch.

bug 3065

Previous cap was 2 sec (default TCP timeout) times the node count
  and divided by 1000. A 9000 node job would have the messages
  spread out over 18 seconds. This change caps the spread at
  5 seconds and assumes the normal TCP logic can handle the rest
bug 3044

If the overhead of determining the hostlist for a given task list
is too high, then report a hostlist of "Unknown" instead. If the
overhead is too high, then srun will become unresponsive and communications
will timeout/fail.
bug 3044

Modify srun task completion handling to only build the task/node string for
    logging purposes if it is needed. Modified for performance purposes.
bug 3044

Add get_log_level() function to return the highest LOG_LEVEL_* used
for any logging mechanism.

This reverts commit 1ec2a4ae.

Conflicts:
	src/api/step_launch.c

Bug 3063.

In scontrol show nodes.

Restructure srun command locking for task_exit processing logic for improved
  parallelism. This change decreases the amount of time consumed by serial
  logic by 2 orders of magnitude.
bug 3044

Grab federations from db at startup instead of waiting for db_update and
load from state if the db is down.

Instead of making a separate copy. All of the cluster_recs are now in
the federation_rec with a pointer to the local cluster rec.

Select federations base off which clusters belong to them.

Preserve node "RESERVATION" state when one of multiple overlapping
    reservations ends. Previous logic would clear the node's
    RESERVATION state flag when any one of the reservations on the
    node ended rather than keeping the node in RESERVATION state
    until the last reservation ended.
bug 3057