Update versions to Django 1.7, Ubuntu Trusty 14.04, Postgres 9.3
Add '/dev/zero'-ing of free space. Saves around 130MiB.
Merge branch 'v2.2_ubuntu14.04_django1.7.1' of https://github.com/nimasmi/vagrant-django-base into nimasmi-v2.2_ubuntu14.04_django1.7.1
Merge branch 'nimasmi-v2.2_ubuntu14.04_django1.7.1'