Hello.

I found a problem with chunk transfer encoding and pipelining. Scenario:
1. Start some pipelined requests.
2. First request is sent.
3. Server responses with chunked encoding.
4. ConnectBits chunk flag is set. But response is not completely
received, so we continue reading.
5. Second request is sent and do_complete() is called. Chunk flag is cleared.
6. Now remaining part of the first response is interpreted incorrectly.

After a timeout connection is closed and restarted.

To fix this I moved chunk and other request specific flags to
SingleRequest struct. And no_body is completely removed, opt_no_body
is used instead.

Regards,
  Dmitry