Add Kaminari

Whilst we won't be using this gem for its scopes,
it provides a robust set of view helpers for
generating pagination, which will save us a lot
of time.
Allow the "page" param to be passed to the Need API

The Need API paginates using the "page" parameter,
so allow this to be passed through to the API when
it's requested.
Add helper to render Kaminari pagination

Use pagination metadata from the GdsApi::Response
object to create a Kaminari::Helpers::Paginator
instance, and render pagination.
Add pagination to the need index page

This renames browsing_needs.rb to browsing_needs_test.rb
so that it will actually be run as part of rake test

This also includes generated Kaminari views for
pagination so that they render Bootstrap-friendly
markup.
Bump gds-api-adapters
Fix integration test definition
Stop the pagination method blowing up when 'needs' is nil
Merge pull request #29 from alphagov/pagination

Paginate needs from the Need API