Include Rack::Response::Helpers in responses

[scttnlsn]

This includes Rack::Response::Helpers methods in the Airborne responses. This enables the use of matchers like those commonly used with ActionDispatch::TestResponse.

i.e.


expect(response).to be_success
expect(response).to be_redirect
expect(response).to be_error
# etc.

A few other notes:

• I added a rest_client_options setting (currently being used to set max_redirects)
• I had to change the way that the requester module is accessed in base.rb. I was encountering an issue in the specs where once Airborne.configuration.rack_app was set it impacted other specs (that expected this value to be nil). I believe this issue is not showing itself on master since rack_sinatra_spec.rb is loaded last.

[coveralls]

Coverage increased (+0.05%) to 99.019% when pulling 731802f on scttnlsn:rack-helpers into 3cc4112 on brooklynDev:master.

[coveralls]

Coverage increased (+0.05%) to 99.019% when pulling 1eb107d on scttnlsn:rack-helpers into 3cc4112 on brooklynDev:master.

[scttnlsn]

Fixed the merge conflicts here. Any interest in this PR?

[coveralls]

Coverage increased (+0.05%) to 99.023% when pulling a55c7a2 on scttnlsn:rack-helpers into 55311ac on brooklynDev:master.