Add pip requirements files

Two separate files are created:

- the ``requirements-dev.txt`` file keeps requirements for a development
  environment
- the ``requirements.txt`` file keeps the requirements for a production
  environment
Add a basic Vagrantfile

In order to provide a uniform development environment for all
developers, a Vagrant config is provided that can make it easy
to spin up a VM containing all requirements of the project.
Add a bootstrap script to provision a blank Vagrant box

The bootstrap script takes care of installing all system-wide
dependencies to the Vagrant box on first boot. It also sets up the
project's dependencies.
Add a convenience script for starting up a dev server

The script in conjunction with the Vagrant file port-forwarding
configuration makes a development server started on the Vagrant VM
accessible from the host machine at http://localhost:8888
Add documentation for using the Vagrant development box
Merge branch 'feature/dev-environ-setup' into develop