[FEATURE] Refactor out http client to separate repo.
[FEATURE] Refactor integration tests to gateway-data and gateway-data-http-adapter.
Merge pull request #23 from geertweening/small-gateway-fixes

Small gateway fixes
[CHORE] Bump dependency version.
Merge branch 'master' of github.com:ripple/ripple-gateway
[CHORE] Bump patch.
[CHORE] Bump dependency and patch.
[CHORE] Bump dependency, patch.
[FEATURE] Remove models from outgoing payment worker.
[FEATURE] Remove models from incoming listener worker.
[CHORE] Add ripple-rest-client package.