Stronger support for zero-performance-penalty output, and fixes and

Stronger support for zero-performance-penalty output, and fixes and
simplifications for the "muzzled" (i.e. competition) design, which had
been broken.  Addition of some new unit test bits to ensure that
nothing is ever called in muzzled builds, e.g. things like

  Warning() << expensiveFunction();

Also, fix some compiler warnings.