ENH: reactionThermo: Single component mixture

This mixture allows a reacting solver to be used with a single component
fluid without the additional case files usually required for reacting
thermodynamics.

reactionThermo: Instantiated more single component mixtures

ENH: reactionThermo: Select singleComponentMixture as pureMixture

A pureMixture can now be specified in a reacting solver. This further
enhances compatibility between non-reacting and reacting solvers.

To achieve this, mixtures now have a typeName function of the same form
as the lower thermodyanmic models. In addition, to avoid name clashes,
the reacting thermo make macros have been split into those that create
entries on multiple selection tables, and those that just add to the
reaction thermo table.