Segmented response for GET request with transfer-encoding: chunked

[ewilazarus]

Whenever attempting to GET a resource, on the response assembly, gentlemen invokes EnsureResponseFinalized, which works perfectly for the majority of use cases.

However, when the response uses a transfer-encoding: chunked strategy, the response should only be finalized once all chunks have been processed.

[h2non]

This should be fixed via #21.