Commented Feature: ApiController.Created should accept relative URI [1627]

The Location header for HTTP 201 supports relative URIs, but the current code for ApiController.Created (which takes a string URI) does not.
Comments: I have verified that `Created(new Uri("foo", UriKind.Relative), make);` works and the location in the response headers would be `foo`. It seems that it is only a problem of how to create the `Uri`...