Fix i18n parse errors when parsing locale files (en/pt)
Add Vagrantfile optimizations

Change default ruby version to the latest 1.9.3 patch release
(1.9.3-p392) and also install de 2.0.0 version for testing purposes.

Install set_locale cookbook, which automatically install UTF-8 locale
on the machine to avoid PostgreSQL LATIN1 error when creating a
database. This cookbook already includes postgresql but is necessary to
put the pg cookbook on the Chefile.

Remove postgres database configuration as we're now doing this through
the rake db:create task (much better, btw).

Add heroku gem. This will allow deployments using the virtual machine.

Add X Virtual Frame Buffer (XVFB) to run cucumber features on a
headless environment.
Change cookbook for firefox.
Merge pull request #137 from runeroniek/vagrant_configuration

Improve Vagrant configuration