Document release process.

Fixes #292.

This is mostly an initial sketch for discussion.

This also at least partially addresses #86, #87, #126, #277.
Add a note explaining how to install the copy repo. See https://github.com/ClusterHQ/flocker/blob/master/vagrant/base/bootstrap.sh#L9 

````
curl https://copr.fedoraproject.org/coprs/tomprince/hybridlogic/repo/fedora-20-x86_64/tomprince-hybridlogic-fedora-20-x86_64.repo >/etc/yum.repos.d/hybridlogic.repo
```