Edited Issue: Add a Request.CreateResponse overload that takes the content CLR type as parameter. [883]

Request.CreateResponse<T> doesn't use the runtime type of the object for content-negotiation. This would be an issue when the formatter doesn't responds to CanWriteType(typeof(object)) with false (example ODataMediaTypeFormatter). An example scenario can be found [here](https://gist.github.com/raghuramn/5084608).

Having a non-generic overload where we can specify T would be useful.