First attempt at creating my own box

        packer build INE-ubuntu-12.04-amd64.json

... worked fine, with one minor bump: It complained about not being able
to download the VMware tools.  That was easily fixed by following the
instructions in the error message (yay!).  tl;dr: start an existing
linux vm, have it install or update the vmware tools, then run packer
again:

        packer build --only=vmware-iso INE-ubuntu-12.04-amd64.json