Add basic Vagrant provisioning script.

I added a basic Vagrantfile with provisioning script that I copied from another project of mine. It works out of the box and sets everything up properly.

Before I continued (by updating the docs to mention the Vagrantfile file, for instance) I just wanted to get a blessing (or curse) from upstream.

This provisioning script will install required packages, create a virtualenv, install the python requirements as well as setup `.bashrc` to automatically activate the environment and cd into the project when you ssh in.