Refs #19 - Accept custom headers
Refs #24 - Add test-helpers.
Refs #24 - Move data-provider to test-helpers directory.
Merge pull request #24 from synapsestudios/feature/24-test-helpers

Move test-helpers from other project
Merge pull request #19 from synapsestudios/feature/19-custom-headers

Support overridden headers
Merge branch 'master' into feature/23-convert-jest-to-karma
Refs #23 - Extract gulp test task setup into separate files.
Refs #23 - Update gateway tests.
Refs #23 - Convert ArrayObject tests.