Implement OPTIONS method handling for web services

[woemler]

Implement OPTIONS method handling for web service requests, to provide info about endpoint functionality.

[woemler]

Thinking of just having OPTIONS method expose the API documentation for each endpoint. Basically, this would return the Swagger docs for the particular endpoint requested, as a JSON document. This will depend on proper SpringFox implementation, which right now is dependent on a bug fix: springfox/springfox#953

[woemler]

Going to look into using the Swagger endpoint documentation for OPTIONS output.