Merge branch 'compute-control'

Rebase changes from earlier ohpc_vagrant repo to create and control
compute nodes in virtualbox.

compute_create

+#!/bin/bash
+
+# Create a network bootable compute node in virtualbox
+#
+# use native VBoxManage because Vagrant doesn't work
+# well with nodes that are meant to boot off the network.
+#
+# node is constrained to boot on the internal "compute" network
+
+nodename="$1"
+
+VBoxManage createvm --name "$nodename" --register
+
+
+VBoxManage modifyvm "$nodename" --memory 4096 --nic1 intnet --intnet1 compute  --nictype1=82540EM --rtcuseutc on
+
+VBoxManage storagectl "$nodename" --name IDE --add ide --controller PIIX4 --bootable on
+VBoxManage storageattach "$nodename" --storagectl IDE --type dvddrive --device 0 --port 1 --medium ~/iso/ipxe.iso

compute_delete

+#!/bin/bash
+
+# Destroy the compute node for ohpc
+
+VBoxManage unregistervm --delete "$1"

compute_start

+#!/bin/bash
+
+# start the compute node for ohpc
+
+VBoxManage startvm "$1"

compute_stop

+#!/bin/bash
+
+# Stop the compute node for ohpc
+
+VBoxManage controlvm "$1" poweroff