Consistent asset precompile across Rails versions
Consistent asset precompile across Rails versions

- Rails 3.2 needs to reset several rake tasks to properly re-run.

- Newer versions of Sprockets writes to stderr so we need to capture output of
  those tasks.

- Rails 3.2's gems don't have `capture_io` defined so we've pulled it
  into `test_helper`

reactjs/react-rails,appslingr/react-lite-rails,reactjs/react-rails,reacuna/react-rails,appslingr/react-lite-rails,mikesea/react-rails,appslingr/react-lite-rails,mikesea/react-rails,reactjs/react-rails,mikesea/react-rails,reacuna/react-rails,reactjs/react-rails,reacuna/react-rails