Add Liberty support.

Add keystone v3 support.  Now you can choose which version of keystone
to run... all combinations tested exception Juno with v3.

Make node type and link speed configurable.

Make token and session timeouts much longer by default (so people don't
get logged out so quickly), but also configurable.

Keystone is now served by WSGI through Apache on Kilo and Liberty.

Memcached keystone token caching is disabled for now; it causes
intermittent problems; so using SQL for now.

Add localhost to /etc/hosts file.  This doesn't cause problems anymore,
if it ever did.

We now use the `openstack' CLI command for >= Kilo, instead of the
per-service client CLI tools.

Stick with ovs agent even in Liberty -- even though the default is now
linuxbridge, it seems.

In general, get rid of nearly all the rest of the cat <<EOF ... EOF
stuff and replace it with crudini --set/--del.  A touch slower, but much
cleaner.

Also in general, improve the Kilo support so that it more closely
matches the docs.