Minor Conflict with rails-api or using Rails::API

[mgorman42]

If built with the rails-api gem or as Rails::API, the ActionController::Helpers is disabled by default.

This causes an issue when trying to render :soap => response, since the soap builders rely on the WashOutHelper module.

A quick fix is to include ActionController::Helpers in the controllers that will be rendering soap response. A more robust fix would be to ensure that it is included when the WashOut::SOAP module is included into the controller.

EDIT: It looks like it does include the ActionController::Helpers if it is rails 5 and the controller is ActionController::API, but this doesn't handle the case of a rails 4 with rails-api gem