Will Bainbridge authored Nov 23, 2017 and Andrew Heather committed Nov 23, 2017

The combustion and chemistry models no longer select and own the
thermodynamic model; they hold a reference instead. The construction of
the combustion and chemistry models has been changed to require a
reference to the thermodyanmics, rather than the mesh and a phase name.

At the solver-level the thermo, turbulence and combustion models are now
selected in sequence. The cyclic dependency between the three models has
been resolved, and the raw-pointer based post-construction step for the
combustion model has been removed.

The old solver-level construction sequence (typically in createFields.H)
was as follows:

    autoPtr<combustionModels::psiCombustionModel> combustion
    (
        combustionModels::psiCombustionModel::New(mesh)
    );

    psiReactionThermo& thermo = combustion->thermo();

    // Create rho, U, phi, etc...

    autoPtr<compressible::turbulenceModel> turbulence
    (
        compressible::turbulenceModel::New(rho, U, phi, thermo)
 ...