The specie molecular mass (Wi) and formation enthalpy (hfi) methods now
return dimensioned scalars. This permits their direct inclusion into
dimensioned field expressions. Non-dimensioned methods have been
retained with a "Value" suffix (i.e., WiValue and hfiValue).
This change makes multiphaseEuler more consistent with other modules and
makes its sub-libraries less inter-dependent. Some left-over references
to multiphaseEulerFoam have also been removed.
