Experiment with some custom Gemfile groups to tidy things up

This is really playing with fire now. Bundler is a finnicky sum'bitch, and
usually punishes me when I try to fix what isn't broken. Here goes nothing.
Try moving some more gems into groups in the Gemfile

Bundler hasn't punished me yet. Might as well push my luck some more.
Add :uploads group to Gemfile and sort the groups
Add version numbers to Gemfile dependencies
Ditch therubyracer Gemfile dependency
Move thin gem into :server Gemfile group
Move rails_12factor dependency in to :server Gemfile group
Move authlogic into :auth Gemfile group
Move video_info into :video Gemfile group
Remove empty :production Gemfile group
See if Heroku works without any JS runtime
Remove jbuilder