[FIX] gitignore config.json
Merge pull request #147 from maxiperezc/add-winston

[Logging] Add robust logging with Winston
[TEST] Test drive correct retryFailedPayment implementation.
[TASK] Bump ripple-rest-client dependency patch version.
Merge pull request #148 from ripple/hotfix-retry-failed-payment

LGTM
[FEATURE] Add ripple rest payment response object spec.
[TASK] Rebase onto develop
[TASK] Remove unused build_payment, send_payment.
[FEATURE] Extract Outgoing Payment Processor.
[FEATURE] Extract OutgoingPayment.
[TASK] Complete refactor of Outgoing Payment.
[TEST] Spec OutgoingPayment and refactor implementation to pass!