Added a boundBox to searchableSurface and implemented in all derived types except searchablePlane, and only as an approximation in searchableCylinder.  Added bounds() function to searchableSurfacesQueries for the overall bounds of a subset of surfaces.  Added closedTriSurfaceMesh type, derived from triSurfaceMesh, except forcing hasVolumeType = true to allow geometrically but not topologically closed or almost closed surfaces to query volumeType.