combustionModel, chemistryModel: Simplified model selection

The combustion and chemistry model selection has been simplified so
that the user does not have to specify the form of the thermodynamics.

Examples of new combustion and chemistry entries are as follows:

    In constant/combustionProperties:

        combustionModel PaSR;

        combustionModel FSD;

    In constant/chemistryProperties:

        chemistryType
        {
            solver          ode;
            method          TDAC;
        }

All the angle bracket parts of the model names (e.g.,
<psiThermoCombustion,gasHThermoPhysics>) have been removed as well as
the chemistryThermo entry.

The changes are mostly backward compatible. Only support for the
angle bracket form of chemistry solver names has been removed. Warnings
will print if some of the old entries are used, as the parts relating to
thermodynamics are now ignored.

tutorials/combustion/reactingFoam/RAS/membrane/constant/combustionProperties

@@ -15,7 +15,7 @@ FoamFile
 }
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
-combustionModel  noCombustion<psiThermoCombustion>;
+combustionModel  none;
 
 
 // ************************************************************************* //