- real bug or compiler bug?

Adding mesh cell inertia calc.

Keeping both functions to ensure that the octant ordering specified in
treeBoundBox is obeyed at the octree level, irrespective of the implementation
of the basic boundBox.

STYLE: move inline functions into boundBoxI.H

STYLE: reduce duplicate methods in treeBoundBox

not required

ENH: directMapped: allow offset specification; allow fieldName specification; allow non-constant interpolation

- otherwise gets flagged as an error by clang

This is to access the face/edge/point status of the nearest at the
same time to ensure a consistent result.

Using getVolumeType query in distanceSurface, not simple normal
dot-product comparison, fails on edges.

Squashed merge of particleInteractions up to
commit e7cb5bcf0315c359539ef1e715e1d51991343391

structuredDecomp uses finiteVolume which uses meshTools which
used to use decompositionMethods

- in preparation for using PackedBoolList