Open requirements up for Ruby and Faraday

Allow backwards compatibility, but also allows testing newer
versions
Fix parse_query change

`Faraday::Utils.parse_query` apparently now returns `nil`
instead of an empty hash. Now we set params to `{}` in that
case.
Fix spec broken by `Faraday` upgrade

This should not be a breaking fix. In fact, I am not sure how this test
ever passed since `BlueKaiMiddleware::Authenticate` was not directly
tied into the `Faraday` instance.
Add docs and bump version
Bump ActiveSupport to later versions of 3.2
Merge pull request #18 from BlueKai/feature/update-faraday

Feature/update faraday

cr @kevinelliott
bump version correctly
Merge release 'v0.6.1' into master