Update Vagrantfile to Ubuntu 14.04 x64
Remove nodejs role
Use defaults for generated env vars
Add var for using system cron
Fix system cron task
Final fix for system cron
Set php5-fpm service to start at boot
Nginx + fpm fixes

* php5-fpm doesn't automatically create directories in /var/run which is
  reset on boot. We lose some organization but it works after rebooting
  which is kind of needed.

* Restart nginx and php5-fpm after WP site creation
Update README to reflect Ubuntu 14.04
Move WP php-fpm confs into wordpress-sites role
Nginx: listen on all interfaces
Use new roots/bedrock Vagrant box
Bump version requirements to latest
Add run_composer option

Previously Composer had to be installed and run locally on the local host
before setting up a dev environment. Now it can be run on the VM for
even more separation.
Turn off sendfile in development

Virtualbox has a bug that could cause static files to not update and
seem cached. References:

* http://wiki.nginx.org/Pitfalls (Virtualbox section)
* http://jeremyfelt.com/code/2013/01/08/clear-nginx-cache-in-vagrant/
* https://github.com/mitchellh/vagrant/issues/351#issuecomment-1339640
Add bash shell to deploy user
Clean up directory/file creation
Improve instructions in README
Remove upgrade role

Upgrading packages means we have no control over the state of packages
which defeats the purpose of consistent environments.
Explicitly require tempfile