Fixed drift and timestamps in periodic carbon dumps.
runner: fixed case revealed by the runner_stress_test where postTerminate
would be invoked twice due to stdInSink not being reset when a wakeup event is
being handled
runner: request closing of stdInSink only if not already closed
http_client: enable an infinite number of recursive requests by using a std::queue rather than an ML::RingBufferSRMW (TRIVIAL)