Add initial framework for a Route plugin to allow messages to be forwarded
using switch topology information.
Use xhash for the node hash instead of the basic hash currently
implemented.
In order to understand the hashing logic of slurm and see where was the
limitation in terms of scalability, I did some tests with cluster sizes
varying from 64 to 64k nodes. I saw the same kind of performance issues
that you saw with large sizes (more than a few thousands nodes).

Looking at the code, I noticed that the hash table of the node records
was not built before the construction of the topology information in
slurmctld ! Making sure that the hash table is present really reduces
the built time.

This patch ensures that and enable to get sub-second built time
for topology information in scenarios that were used to require a
minute before.

I think that using this patch, the load time of slurm confs is less
problematic.
Fix reconfig issue in relation to previous xhash commit
Initial addition of the routing plugins
remove unused variables.
Add missing ()
Make the debug_flags 64 bit
Just playing it safe.
Minor reformatting
run autogen.sh
Add new test to test routing plugin
Add test33.1 to Makefile.am