Tweaks to Cagara's CountPrivateBandwidth patch:

  - Document it in the manpage
  - Add a changes entry
  - No need to log when it is set: we don't log for other options.
  - Use doxygen to document the new flag.
  - Test truth of C variables with "if (x)", not "if (x == 1)".
  - Simplify a complex boolean expression by breaking it up.