Drop DELETE with body, violates HTTP 1.1 spec.

- As per http://tools.ietf.org/html/rfc7231 GET and DELETE payloads have NO defined semantics. So we can't just add some ourselves, this would not be HTTP/1.1 any longer.
- Methods now are POST, add "/remove" to path.
- Comment deletion only returns default response.
Add tests for updating and deleting a comment.
Merge branch 'no-body-for-delete' into api-v2