chtMultiRegionFoam: Added optional hydrostatic initialisation of pressure

Class
    Foam::hydrostaticInitialisation

Description
    Optional hydrostatic initialisation of p_rgh and p by solving for and
    caching the hydrostatic ph_rgh and updating the density such that

        p = ph_rgh + rho*gh + pRef

    This initialisation process is applied at the beginning of the run (not on
    restart) if the \c hydrostaticInitialisation switch is set true in
    fvSolution/PIMPLE or fvSolution/SIMPLE.  The calculation is iterative if the
    density is a function of pressure and an optional number of iterations \c
    nHydrostaticCorrectors may be specified which defaults to 5.

applications/solvers/heatTransfer/chtMultiRegionFoam/chtMultiRegionFoam.C

@@ -46,6 +46,7 @@ Description
 #include "coordinateSystem.H"
 #include "pimpleMultiRegionControl.H"
 #include "pressureReference.H"
+#include "hydrostaticInitialisation.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
@@ -58,9 +59,9 @@ int main(int argc, char *argv[])
     #include "setRootCaseLists.H"
     #include "createTime.H"
     #include "createMeshes.H"
+    pimpleMultiRegionControl pimples(fluidRegions, solidRegions);
     #include "createFields.H"
     #include "initContinuityErrs.H"
-    pimpleMultiRegionControl pimples(fluidRegions, solidRegions);
     #include "createFluidPressureControls.H"
     #include "createTimeControls.H"
     #include "readSolidTimeControls.H"