Merge pull request #40 from grosser/r30

Bring back rails 3.0 support and some small cleanup
FeaturesController#update_all: pass model errors to translation
FeaturesHelper: add arturo_flash_messages helper
Views: use arturo_flash_messages helper
FeaturesHelper: require 'action_view'

https://travis-ci.org/jamesarosen/arturo/jobs/5747404 is failing when
trying to automatically load TagHelper. I can't replicate this locally,
even on the same Ruby, RubyGems, and RVM. My first hypothesis is that
loading action_view will cause the proper dependencies to be loaded.
Gemfile: use rubygems.org directly as source
Merge pull request #41 from jamesarosen/message_cleanup

Message cleanup
NoSuchFeature null-object for cache misses
NoSuchFeature: better translation key for name
Merge pull request #45 from jamesarosen/no_feature

NoSuchFeature null-object for cache misses
Remove Rails 3 support

The builds fail regularly on Travis. If we can get them to pass
reliably, I'm quite happy to revert this.
Travis: don't try to test on Rails 3
Travis: no need to exclude Rails 3 + Rails 2.0.0
Revert "Travis: don't try to test on Rails 3"

This reverts commit 4305c5559a025794df408a9bc31264e79e0469a6.
Revert "Travis: no need to exclude Rails 3 + Rails 2.0.0"

This reverts commit f952752aa9a930df821feba34be9e42827073b36.
Revert "Remove Rails 3 support"

This reverts commit 03f4f0e8efa93d3d635b7b542f14afc7b716060c.
remove requires to go back to autoloading and avoid dependency issues on rails 3