fixedFluxPressure BC: the snGrad is now pushed into the BC from pEqn.H rather than being evaluated in the BC

For DyM solvers phiAbs is replaced by Uf but this conversion is currently not complete

Thermodynamics and sub-models:  Removed "Sp" boundedness corrections on transport, replaced with "bounded Gauss" scheme

so that the effect of the term on the enthalpy equation is optional

At the specie level:
    hs = sensible enthalpy
    ha = absolute (what was total) enthalpy
    es = sensibly internal energy
    ea = absolute (what was total) internal energy

At top-level
    Rename total enthalpy h -> ha
    Rename sensible enthalpy hs -> h

Combined h, hs, e and es thermo packages into a single structure.

Thermo packages now provide "he" function which may return either enthalpy or
internal energy, sensible or absolute according to the run-time selected form

alphaEff now returns the effective diffusivity for the particular energy which
the thermodynamics package is selected to solve for.