change box_url to be the same as controller
change box name to deis-controller for consistency
s/controller/server/g for consistency

this is a base deis box. Since it applies to both controllers and
nodes, there's no need to name the vagrant box one or the other.
This allows users to download the box once and never have to
download it again.
change default box_url. Fixes #581
Merge pull request #582 from opdemand/change-vagrantfile-template-url

change box_url to be the same as controller