- refine definition of patch boundary faces to distinguish between
boundaryFaces() and uniqBoundaryFaces().
* boundaryFaces() for edge to face lookup on boundary edges.
* uniqBoundaryFaces() for accessing quantities such as face areas
or eroding an outer layer
ENH: LabelledItem container, replaces unused 'Keyed' container
- method names in alignment with objectHit, pointIndexHit etc.
Top-level name aligns with labelledTri.