Added Vagrant support

Automated installation in a VM is now working (although quite rudimentary).
Now you can just run::

    vagrant up

to setup the vm, then::

    vagrant ssh

to connect to the vm, and then just initialize the database and
run paster::

    workon ckan
    paster --plugin=ckan db --config=$VIRTUAL_ENV/etc/ckan/development.ini init
    paster --plugin=ckan serve $VIRTUAL_ENV/etc/ckan/development.ini