Merge branch 'develop' into mpi

CMakeLists.txt

doc/pde-solvers.rst

examples/heat-equation/HeatEquationBuildConfigTag.h

examples/heat-equation/tnl-heat-equation-eoc.h

examples/heat-equation/tnl-heat-equation.h

examples/inviscid-flow/eulerBuildConfigTag.h

...ples/transport-equation/transportEquationBuildConfigTag.h

src/Python/CMakeLists.txt

src/Python/pybind11.cmake.in

src/Python/pytnl/CMakeLists.txt

src/Python/pytnl/RawIterator.h

src/Python/pytnl/exceptions.h

src/Python/pytnl/tnl/Array.h

src/Python/pytnl/tnl/CMakeLists.txt

src/Python/pytnl/tnl/EntityTypes.h

src/Python/pytnl/tnl/Grid.h

src/Python/pytnl/tnl/Grid1D.cpp

src/Python/pytnl/tnl/Grid2D.cpp

src/Python/pytnl/tnl/Grid3D.cpp

src/Python/pytnl/tnl/Grid_getSpaceStepsProducts.h