Absolute enthalpy h = hs + hc.

- drop copy components constructors in favour of the xfer versions. Even if
  the caller sends through constant data, if will be automatically promoted
  to xfer (via a copy operation).

  - dropped non-const tmp::clear() in favour of the const version

- use xfer form for calls to resetPrimitives

  - keyedSurface is similar to triSurface, but uses faces
  - meshedSurface is sorted in regions and should be more memory efficient
  - surfMesh is the placeholder name for an OpenFOAM native surface format