- simplified templating, which cleans up code and does not appear to
break any normal user coding.
ENH: unique_ptr instead of homegrown demand-driven handling.
- face_type, point_type (similar to STL value_type, etc).
The naming avoids potential confusion with template parameters.
- rename private typedef from ParentType to MeshReference for more
consistency with polySurface etc.
This class is largely a pre-C++11 holdover. It is now possible to
simply use move construct/assignment directly.
In a few rare cases (eg, polyMesh::resetPrimitives) it has been
replaced by an autoPtr.