Test: run the loopback test with each host API and compare the loop latencies with the reported stream latencies.

Document anomalies below.

This is intended to be part of a review of reported stream latencies #181

||= host api =||= status=||
||alsa || ? ||
||asihpi || ? ||
||asio || ? ||
||coreaudio || ? ||
||dsound || ? ||
||jack || ? ||
||oss || ? ||
||wasapi || ? ||
||wdmks || ? ||
||wmme || ? ||