Add Kaminari support

* Add Kaminari Responder.
* Moved dependencies in the `Gemfile` to the `gemspec` as development dependencies since all gem dependencies should be in the gemspec for gems.

# To Test

In your app, include the Kaminari Responder

```
class AppResponder < ActionController::Responder
  include Responders::KaminariResponder
end
```

Then include the responder in your controller

```
class MyController < ApplicationController
  self.responder = AppResponder
end
```