fix(pip): update location of pip installer

raw.github.com URLs have moved to raw.githubusercontent.com, and
wget was seeing a 301 (Moved Permanently) under the covers. curl
does not automatically follow such a redirect, so the URL change
caused an error for deis/tester, but was benign here.
tests(travis-ci): remove branch restrictions for test runs

We previously restricted travis-ci.org builds to just the `master`
and `release` branches, but that isn't necessary. To help with
developing new integration tests, have Travis build any Deis branch.
docs(contributing): add skip ci tag

You can skip a build on TravisCI by adding the skip ci tag
to the commit message. This formalizes that process in the
documentation.

ref: http://docs.travis-ci.com/user/how-to-skip-a-build/
docs(contributing): split out DCO
fix(test): specify machine IPs

The Rakefile breaks for cloud providers, as we used the HOST
for both the cluster domain and a list of hosts. Since etcd/fleet
now listen exclusively on the `private_ipv4` interface, connecting
on the public domain doesn't work.

This commit adds a new environment variable, `DEIS_TEST_HOSTS`,
to pass in the hosts to the creation of the cluster.
refactor(contrib/rackspace): create private network on Rackspace

Previously, we were creating servers using the default Rackspace
ServiceNet as the private network. This means that they are feasibly
accessible by other servers on that network. This commit ensures
we are creating a new, private network for deis and not connecting
to the ServiceNet any longer.

closes #891
fix(docker): use btrfs inside builder

We have seen mixed usage of aufs and btrfs cause problems before. On
CoreOS, btrfs rules the day, so use that.
Merge pull request #886 from deis/docs-no-ci

docs(contributing): add skip ci tag
fix(ec2): add explicit 100GB root volume

By default the m3 instances (of all types) use an 8GB root volume.
The SSD volume is unused and located at /dev/xvdb. This PR changes
the 8GB root volume to 100GB, providing enough storage for a basic
Deis cluster.

fixes #882
Merge pull request #889 from deis/test_hosts

fix(test): specify machine IPs
feat(client): add --app option to apps:run

All of the other apps commands have a --app option. This commit
introduces that option to the apps:run command as well.

fixes #722
Merge pull request #895 from deis/fix-ec2-space

fix(ec2): add explicit 100GB root volume
docs(README): install nfs on Ubuntu

Ubuntu does not have nfs support by default. You must install nfs-kernel-server
to get nfs support. Adding this to the documentation will make the process for
developing Deis on Ubuntu a little clearer.

closes #896
Updated CHANGELOG.md.
Switch master to v0.9.0.
Merge pull request #893 from deis/btrfs-builder

fix(docker): use btrfs inside builder
Merge pull request #900 from hyao/master

docs(README): install nfs on Ubuntu
Merge pull request #885 from deis/travis-integration

tests(travis-ci): remove branch restrictions for test runs
Merge pull request #880 from deis/pip-url-moved

fix(pip): update location of pip installer
Merge pull request #892 from deis/rs_private_network

refactor(contrib/rackspace): create private network on Rackspace