development; issue #374: Refactor 'make hack' making Vagrantfile and VM more useful
development; issue #374: Upgrade development VM box to Ubuntu-13.04 with kernel 3.8
development; issue #374: Update VM documentation
Merge pull request #493 from dotcloud/374-developer-environment

* hack: development; issue #374: Refactor 'make hack' making Vagrantfile and VM more useful