Some vagrant polish to improve stabilty

Bundler is being run as root due to an error with the rbenv
LWRP/cookbook (see: ). This works around that by fixing the permissions
after `bundle install`.  Notable changes in this commit:

 * Update all cookbooks
 * Update all gems (and Gemfile.lock)
 * Use node var (rails[:deploy_to]) for nginx server root
 * Modify passenger cookbook to better support rbenv/nginx, remove rvm
 * Set node vars for bundle_path, deploy_to, and deploy_user
 * Remove unused deb url/shas from elasticsearch node config
 * Add vagrant to rbenv group via node config / rbenv cookbook
 * Put wordnet cookbook in front of answers in run list
 * Reduce swap space to 2 GB
Add option to use a pre-built vagrant box
Add env variable to specify vagrant box url
Merge branch 'feature/vagrant_polish' into dev
Packaging bundle in vendor to speed up travis runs