Merge master

.gitlab-ci.yml

CMakeLists.txt

cmake/FindOpenMesh.cmake

python/lbmpy_walberla/additional_data_handler.py

src/core/DataTypes.h

src/core/mpi/CMakeLists.txt

src/core/mpi/Datatype.h

src/core/mpi/MPIManager.cpp

src/core/mpi/MPIManager.h

src/core/mpi/MPIOperation.h

src/core/mpi/MPIWrapper.cpp

src/core/mpi/MPIWrapper.h

src/core/mpi/Operation.h

src/core/mpi/Reduce.h

src/core/timing/Timer.h

src/domain_decomposition/BlockStorage.h

src/field/distributors/KernelDistributor.h

src/field/distributors/NearestNeighborDistributor.h

src/field/interpolators/KernelFieldInterpolator.h

src/field/interpolators/NearestNeighborFieldInterpolator.h