1) PhaseIncompressibleTurbulenceModel class was changed to use
uniform alpha and non-uniform rho templates. This fits the need
of incompressible two phase turbulence models.
2) A new type DPMIncompressibleTurbulenceModel was created for
non-uniform alpha and uniform rho. It is used in single phase flows
in DPM solvers where alpha represents the volumen occupancy.
3) A new type incompressibleRhoTurbulenceModel was created where
non-uniform rho is allowed.
4) A new base templated turbulent class for two-phase VOF named
VoFphaseTurbulentTransportModel was implemented which is created
templating on PhaseIncompressibleTurbulenceModel and
incompressibleRhoTurbulenceModel
5) In order to make the chnage to rho based VOF turbulence a help
class was added incompressibleInterPhaseTransportModel templated
on the mixing.