Refs #2480 - Display default values and mandatory props in alg diags.

Take same definition of mandatory as WikiMaker, i.e. when a property needs
input from the user or else a red asterisk will appear.

Account for instances of EMPTY_* and *_MAX macros.  Catch a few that even
WikiMaker doesn't.
Merge branch 'feature/2480_show_required_props_and_default_vals_in_alg_diags' into develop