Specs (except those for Railtie) pass against Rails 3.0
Most specs pass in Rails 3.2 and 4.0

- Rails 3.0 deprecated request_uri in favor of fullpath
- Rails 3.1 changed default format in Active Resource
  to JSON
Header specs pass in Rails 4

Need to pass the date differently, see
https://github.com/rails/rails/issues/11110#issuecomment-20044511