ENH: Added new createViewFactors utility

Creates view factors for the view factor radiation model.

User-selectable models:

- raySearchEngine: model to generate rays, i.e. face-to-face connections
- viewFactorModel: model to compute the view factors

For visualisation, use:

- Write the view factors as a volume field

    writeViewFactors    yes;

- Write the rays using OBJ format:

    writeRays       yes; // default = no

Participating patches must be in the \c vewFactorWall group, i.e. using the
\c inGroups entry of the "\<case\>/polyMesh/boundary" file.

\verbatim
myPatch
{
    type            wall;
    inGroups        2(wall viewFactorWall);
    ...
}
\endverbatim

Reads:

- <constant>/viewFactorsDict : main controls
- <constant>/finalAgglom : agglomeration addressing (from faceAgglomerate)

Generates:

- <constant>/F : view factors (matrix)
- <constant>/mapDist : map used for parallel running
- <constant>/globalFaceFaces : face addressing

applications/utilities/preProcessing/createViewFactors/viewFactorModels/Make/files

@@ -0,0 +1,12 @@
+raySearchEngine/raySearchEngine/raySearchEngine.C
+raySearchEngine/raySearchEngine/raySearchEngineNew.C
+raySearchEngine/voxel/voxelRaySearchEngine.C
+/* raySearchEngine/nonUniformVoxel/nonUniformVoxelRaySearchEngine.C */
+/* raySearchEngine/allToAll/allToAllRaySearchEngine.C */
+viewFactorModel/viewFactorModel/viewFactorModel.C
+viewFactorModel/viewFactorModel/viewFactorModelNew.C
+viewFactorModel/viewFactor2AI/viewFactor2AI.C
+viewFactorModel/viewFactor2LI/viewFactor2LI.C
+viewFactorModel/viewFactorHottel/viewFactorHottel.C
+
+LIB = $(FOAM_LIBBIN)/libviewFactorModels

applications/utilities/preProcessing/createViewFactors/viewFactorModels/Make/options

@@ -0,0 +1,14 @@
+EXE_INC = \
+    -I$(LIB_SRC)/finiteVolume/lnInclude \
+    -I$(LIB_SRC)/surfMesh/lnInclude \
+    -I$(LIB_SRC)/meshTools/lnInclude \
+    -I$(LIB_SRC)/parallel/distributed/lnInclude \
+    -I$(LIB_SRC)/fileFormats/lnInclude
+
+EXE_LIBS = \
+    -lfiniteVolume \
+    -lsurfMesh \
+    -lmeshTools \
+    -ldistributed \
+    -lradiationModels \
+    -lfileFormats