fix(contrib): check that coreos/user-data has a discovery_url set
feat(docker registry): add Vagrantfile for Docker registry

Adds a contrib/docker-registry directory with a Vagrantfile that
configures and starts a VM with the Docker registry service.
feat(contrib) Spin up an ELB

Fixes #1139
Use TCP > HTTP
chore(*): rely on etcdctl in deis/base

As of deis/base#4, etcdctl v0.4.2 includes the --no-sync option.
We no longer need to install an etcdctl branch just to get this
option.
fix(logger): turn off verbose untar'ing

untar'ing go's tarball dumps out a lot of unneeded lines. This
cleans up the build process a bit.
Merge pull request #1143 from itsmeduncan/1139-ec2-elb-autoprovision

feat(contrib) Spin up an ELB
chore(contrib): bump coreos to v343.0.0

```
core@deis-1 ~ $ docker version
Client version: 1.0.0
Client API version: 1.12
Go version (client): go1.2
Git commit (client): 63fe64c
Server version: 1.0.0
Server API version: 1.12
Go version (server): go1.2
Git commit (server): 63fe64c
core@deis-1 ~ $ fleetctl --version
fleetctl version 0.4.0
core@deis-1 ~ $ etcdctl --version
etcdctl version 0.4.3
```
fix(scheduler): remove arping hack

This is no longer required for v1.0.0
chore(contrib): bump coreos to v349.0.0

Still waiting on Rackspace, as they're still on v338.0.0 as of
this commit.
chore(builder): bump to docker v1.0
Merge pull request #1105 from deis/check-discovery-url

fix(contrib): check that coreos/user-data has a discovery_url set
fix(builder): set docker version explicitly
Merge pull request #1169 from deis/coreos-343.0.0

chore(contrib): bump coreos to v349.0.0
feat(Makefile): move rsync from Vagrantfile to Makefile

Moves rsync from the Vagrantfile to the Makefile, enabling
development to occur on non-local Deis deployments (EC2, Rackspace,
etc.).

TESTING: ensure `make build` works the same way, both for the
main Makefile and the individual component Makefiles. To test for
a remote deployment:

```console
$ DEIS_HOSTS="54.12.21.12 54.13.11.4 55.61.2.4" make build
```

You can also test the `make rsync` target directly.

closes #1020
docs(contrib): fix DEIS_HOSTS example

Previous example was invalid.
chore(contrib): update Rackspace to 349
Merge pull request #1194 from deis/rackspace_349

chore(contrib): update Rackspace to 349
chore(Makefile): clean up rsync excludes
docs(README): denote `make build` as optional

It's only necessary when making code changes.