- tutorials based on squareBend used Default_Boundary_Region explicitly
defined since they predated the defaultPatch renaming (2008).
The name 'Default_Boundary_Region' was for convenience as the default
name when converting to PROSTAR or CCM formation, but can now be
changed to something more generic.
- define wall boundary conditions for squareBend using a general regex
to allow future splitting of wall types by name.