Also
- added documentation to header
- added 'resultName' to enable user to specify alternative name for
  output field

Also added 'resultName' to enable user to specify alternative name for
output field

Also added output of diameter info, D10, D32 and DMax

Note: added as a pointer since the list operates in multiple modes, e.g.
as constructed by the Time database and 'outside' by
execFlowFunctionObjects

Class now provides helper functions to generate files on-the-fly by
function objects, as opposed to attempting to control all files needed
by the function object (earlier implementation lead to over-complication
and was error prone)

This new class provides function objects with a database (dictionary)
to store current state information to enable smooth restart behaviour.
Additionally, current results can be stored so that they can be accessed
between different objects.

functionObjects only get detroyed when the runTime gets destroyed. So the
mesh is already destroyed and we cannot hold e.g. a volScalarField since
that will try to 'checkOut' from the objectRegistry(=mesh) upon destruction.
Note that we only see this in chtMultiRegionFoam.

This bc was in compressible turbulence library which made it dependent
on liquidProperties. It was moved to a separate library since it is only
used in a single tutorial.

Feature snappy hex mesh gap refinement

Adding automatic gap refinement capability

See merge request !2

Feature snappy hex mesh

It's got all of the VW snappyHexMesh developments in it.

Not yet the automatic-gap refinement.

See merge request !1

ENH: Adding humidityTemperatureCoupledMixed BC and directionalPressureGradientExplicitSource and the corresponding tutorial
tutorials/heatTransfer/chtMultiRegionFoam/windshieldCondensation

Original fix (http://www.openfoam.org/mantisbt/view.php?id=1780)
did an increment to create a new communicator. This might
access the communicator-to-mpi_structure tables in PstreamGlobals.H outside
range. Instead allocate and release communicator.

Initial implementation. Still goes wrong on r1 == r2.

- shoot rays to nearest point on surface and two perpendicular rays
  (instead of always shooting in the 3 coordinate directions)

- avoid bleeding through the surface intersection

1. multi-ray shooting. It now shoots rays in all the 3 coordinate directions
from the cell centre. Before it would shoot just a single ray from the
nearest point on the surface, going through the cell centre.

There is a cost overhead in that now it shoots 6 rays (+-x, +-y, +-z)
instead of just 1.

2. bleeding of refinement. It marks the cells inside a gap and walks out
the gap-size to neighbouring cells (which are just outside the gap). This
should make for a smoother refinement pattern.

Merge branch 'feature-snappyHexMesh' of develop.openfoam.com:Development/OpenFOAM-dev-OpenCFD into feature-snappyHexMesh

The start of the layer addition loop does a synchronisation of the wanted
displacement. This also does a truncation of the displacement if it is <
minThickness. At the first iteration the displacement was initialised to
vector::one which might trigger the truncation logic (and then disable
extrusion altogether). Instead we now initialise the displacement to
vector::GREAT before entering the synchronisation.