[Vagrantfile] skydns fixes and stuff

Make it so that the name argument to the agent is a name,
so when it gets registered in skydns it's not weird.

Also point local dns to the skydns server and register the
machine name (ubuntu-14) in it.
Add support for CircleCI

CircleCI gives us faster, more reliable builds than Travis, since it has a
higher memory limit (4G vs 2G) and also has Docker running natively, rather
than us having to hack it into a usermode Linux instance.

* Add circle.yml configuration. It sets environment variables, ensures that
  Docker is exposed via TCP, and runs our Maven commands.

* Add a circle build profile.
Move gpg signing to profile

So that you don't need to have the keys just to build/install anything.
Also done as profile because if we just removed the <executions> it has
been observed to produce bad GPG signatures.
Collect artifacts for CircleCI

Collect generated Debian packages, and any JAR's that end in a version or
snapshot number (that is, not sources, javadoc, or shaded).
CircleCI: Add parallelism for tests

Also move stuff into circle.sh since it's more complicated now and hard to
express in yaml.