Implements streaming CSVs.

Allows unlimited downloads of CSV data using ActiveRecord batch APIs and ActionController response streaming.

Works on Rails 3.2+
Actually pass the options to generate_line.
Make the meat and potatoes of streaming protected.
Add no-cache header to streaming CSV responses.
Disable downstream response buffering of stream
Cache Bundler to S3 on Travis
Workaround for CSV#generate encoding issue.
Add integration tests
maybe the latest Bundler isn't needed anymore?
Cache the test app to S3 on Travis
turns out tar remembers the folder structure!
create proper URLs
actually save files when `:as` isn't provided
update `rake setup` to not run if test app exists
Add encode options
Add header_action method for panels
Use Capybara to better test panel rendering
allow Rails 4.1.x versions to be installed
Merge pull request #3115 from agrobbin/rails-4-1-1

allow Rails 4.1.x versions to be installed
test Rails 3.2.18