Make waLBerla fit for SuperMUC-NG

See merge request walberla/walberla!207

- workaround seems to be not necessary any more, for recent IntelMPI versions
- the workaround did not play with CMake's try_compile function, which tries to compile some test programs to check for compiler features
  The workaround added '-include mpi.h' to the compile flags, which are also used by try_compile, but try_compile does not set include directories with "-I"
  This lead to the problem, that for example the OpenMP flag was not correctly determined, since there the try_compile mechanism is used

Add directory 'executiontree' to .clang-format

See merge request walberla/walberla!206

Fix too narrow CLI boundary condition assertion

See merge request walberla/walberla!205

add Visual Studio 2019 to the ci

See merge request walberla/walberla!204

Don't use __has_include macro if it's not defined

See merge request walberla/walberla!203

disabled OpenMP parallelization for intel 17
in a non performance critical section

Add .clang-format

See merge request !202

added IProbe communication for varying size communication

See merge request !198

Fix use of references in BoundaryHandlingCollection's constructor

See merge request !201

[API] Change BodyTypeTuple of Union to variadic template

Closes #87

See merge request !189

Michael Kuron authored Mar 28, 2019 and Sebastian Eibl committed Apr 17, 2019

so Union<std::tuple<Sphere,Box>> becomes Union<Sphere,Box>

[API] Replace boost tuple and allow building Walberla without Boost

Closes #48

See merge request !197

Add /.idea to .gitignore

See merge request !200

It is not actually used anywhere (since the removal of the old pe), is very hard to read, and essentially contains a custom clone of std::tuple.
If it is ever needed, it could easily be re-implemented using std::tuple and variadic templates in significantly less code.