Add .clang-format file and apply to VirtualFluidsCPU.

.clang-format

src/cpu/VirtualFluidsCore/BoundaryConditions/BCAdapter.h

src/cpu/VirtualFluidsCore/BoundaryConditions/BCAlgorithm.cpp

src/cpu/VirtualFluidsCore/BoundaryConditions/BCAlgorithm.h

src/cpu/VirtualFluidsCore/BoundaryConditions/BCArray3D.cpp

src/cpu/VirtualFluidsCore/BoundaryConditions/BCArray3D.h

src/cpu/VirtualFluidsCore/BoundaryConditions/BCFunction.cpp

src/cpu/VirtualFluidsCore/BoundaryConditions/BCFunction.h

src/cpu/VirtualFluidsCore/BoundaryConditions/BCProcessor.cpp

src/cpu/VirtualFluidsCore/BoundaryConditions/BCProcessor.h

...rtualFluidsCore/BoundaryConditions/BoundaryConditions.cpp

...VirtualFluidsCore/BoundaryConditions/BoundaryConditions.h

.../VirtualFluidsCore/BoundaryConditions/NoSlipBCAdapter.cpp

...pu/VirtualFluidsCore/BoundaryConditions/NoSlipBCAdapter.h

...irtualFluidsCore/BoundaryConditions/NoSlipBCAlgorithm.cpp

.../VirtualFluidsCore/BoundaryConditions/NoSlipBCAlgorithm.h

...irtualFluidsCore/BoundaryConditions/VelocityBCAdapter.cpp

.../VirtualFluidsCore/BoundaryConditions/VelocityBCAdapter.h

...tualFluidsCore/BoundaryConditions/VelocityBCAlgorithm.cpp

...irtualFluidsCore/BoundaryConditions/VelocityBCAlgorithm.h