fix(contrib): check that coreos/user-data has a discovery_url set
feat(contrib) Spin up an ELB

Fixes #1139
Use TCP > HTTP
Fixed grammatical mistake
Fixed typo where .com was added twice
Merge pull request #1188 from Imdsm/patch-2

docs(using): fixed typo where .com was added twice
Merge pull request #1187 from Imdsm/patch-1

docs(installing): fixed grammatical mistake
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
chore(contrib): update Rackspace to 349
Merge pull request #1194 from deis/rackspace_349

chore(contrib): update Rackspace to 349
feat(*): allow custom component images

Pull image names for Deis components from etcd, defaulting to the
stock Deis component images. This enables users to supply their own
router, for instance, simply by setting an etcd key:

/deis/{component}/image

Also, the Deis release version is now stored in /etc/deis-release.
This is by default appended when getting the image names for Deis
components, but can be overridden if set in etcd at /deis/release.