the grids now store their number of layers, such that different refinements have different number of layers

implements a new flag in the grid that controls wheter the inner region is defined by triangular mesh or primitive

changes the call structure for findInnerNodes() in inital() to allow conglomerates of primitives and triangular meshes

# Conflicts:
#	src/GridGenerator/grid/BoundaryConditions/Side.cpp
#	src/GridGenerator/grid/GridBuilder/LevelGridBuilder.cpp
#	src/GridGenerator/grid/GridBuilder/MultipleGridBuilder.cpp
#	src/VirtualFluids_GPU/LBM/Simulation.cpp
#	src/VirtualFluids_GPU/Output/FileWriter.cpp
#	targets/apps/HULC/main.cpp

# Conflicts:
#	src/GridGenerator/grid/GridBuilder/MultipleGridBuilder.cpp
#	targets/apps/HULC/main.cpp