Rearrange classes for request and response processing

Rearrange classes for request and response processing

RequestContext object is the only one passed from SocketManager
to Request execute() method.
Response object is passed to Protocol through
RequestContext::returnResponse().
Response queue is managed automaticaly in RequestContext class.
Request derivatives don't need to handle queues.
ResponseTaker::appendResponseToBuffer() methods need to take
additional queue object as parameter as it is no longer
part of response object.

Change-Id: I15af84c315a55284d4dccff670537e47c60c6b70