o Minor bugfixes (relay):
    - Do not try to parallelize workers more than 16x without the
      user explicitly configuring us to do so, even if we do detect more than
      16 CPU cores. Fixes bug 19968; bugfix on
      0.2.3.1-alpha.


  o Minor bugfixes (testing):
    - Avoid a unit test failure on systems with over 16 detectable
      CPU cores. Fixes bug 19968; bugfix on
      0.2.3.1-alpha.