Ruby: Upgrade to 2.1.2

2.1.1 has been deprecated on Heroku in favour of 2.1.2
Remove references to localtunnel from Gemfile

The gem has been yanked from rubygems.org
Upgrade Rails to 3.2.19

There have been multiple security releases since 3.2.16
Update New Relic agent and config
Remove vendor/plugins
Initial rebranding
Allow HOST to be set by CANONICAL_HOST environment variable
fixup! Allow HOST to be set by CANONICAL_HOST environment variable