ENH: vtkCloud function object (issue #866)

• writes lagrangian data in VTP format during a simulation. In parallel, all data are written from the master.

• also emits a file series (supported by paraview 5.5 and later), which helps maintain a correspondence between VTK files and their time values.

src/functionObjects/lagrangian/Make/files

@@ -2,4 +2,6 @@ cloudInfo/cloudInfo.C
 icoUncoupledKinematicCloud/icoUncoupledKinematicCloud.C
 dsmcFields/dsmcFields.C
 
+vtkCloud/vtkCloud.C
+
 LIB = $(FOAM_LIBBIN)/liblagrangianFunctionObjects