Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1505

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1402

Currently these vectors are generated at the same time as the wall-distance field
by the same run-time selected algorithm.  This will be changed so that the wall-reflection
vectors are only generated and stored if required.

When using models which require the wallDist e.g. kOmegaSST it will
request the method to be used from the wallDist sub-dictionary in
fvSchemes e.g.

wallDist
{
    method meshWave;
}

specifies the mesh-wave method as hard-coded in previous OpenFOAM versions.

In preparation for run-time selectable methods

to support improved discretisation in pEqn and implicit treatment in the phase-fraction equation

Provided by Juho Peltola