compressibleInterFoam: Add support for run-time selectable equation of state

...ations/solvers/multiphase/compressibleInterFoam/Allwclean

...cations/solvers/multiphase/compressibleInterFoam/Allwmake

...ons/solvers/multiphase/compressibleInterFoam/Make/options

applications/solvers/multiphase/compressibleInterFoam/TEqn.H

...mpressibleInterFoam/compressibleInterDyMFoam/Make/options

...rFoam/compressibleInterDyMFoam/compressibleInterDyMFoam.C

.../multiphase/compressibleInterFoam/compressibleInterFoam.C

...s/solvers/multiphase/compressibleInterFoam/createFields.H

applications/solvers/multiphase/compressibleInterFoam/pEqn.H

...se/compressibleInterFoam/phaseEquationsOfState/Make/files

.../compressibleInterFoam/phaseEquationsOfState/Make/options

...ssibleInterFoam/phaseEquationsOfState/constant/constant.C

...ssibleInterFoam/phaseEquationsOfState/constant/constant.H

...mpressibleInterFoam/phaseEquationsOfState/linear/linear.C

...mpressibleInterFoam/phaseEquationsOfState/linear/linear.H

...terFoam/phaseEquationsOfState/perfectFluid/perfectFluid.C

...terFoam/phaseEquationsOfState/perfectFluid/perfectFluid.H

...onsOfState/phaseEquationOfState/newPhaseEquationOfState.C

...ationsOfState/phaseEquationOfState/phaseEquationOfState.C

...ationsOfState/phaseEquationOfState/phaseEquationOfState.H