Adding VMS+Cobalt support.

This will install the additional packages necessary to enable VMS
on all the worker nodes (+ API extensions, horizon extensions).
All installation is dependent on a vms_key being present in the
environment. If this key is not provided, nothing will be installed.

Signed-off-by: Adin Scannell <adin@scannell.ca>
Merge pull request #52 from amscanne/vms_support

Add (optional) virtual memory streaming support.