OpenMPI 3.0 by default does not allow running with more processes than CPUs

Resolve "No regex_replace in GCC 4.8"

Closes #38

See merge request walberla/walberla!58

New field utilities

See merge request walberla/walberla!61

Resolve "Suppress undefined behaviour warning in Send/Recv Buffer"

Closes #39

See merge request walberla/walberla!59

New pe coupling functionalities

See merge request walberla/walberla!56

Always initialize bugfix

See merge request walberla/walberla!57

Resolve "Fix regex wrap in povrayFileCompressor"

Closes #36

See merge request walberla/walberla!55

calculateSize was called but may have been uninitialized

Fix "possible misuse of comma operator" warning

See merge request walberla/walberla!54

Wrap likwid header

See merge request walberla/walberla!53

pe_coupling: Improved reconstruction

See merge request walberla/walberla!51

Mg convergence

See merge request walberla/walberla!49

fixed timingtree reduce for non mpi builds and single process runs

See merge request walberla/walberla!50

wrap regex

See merge request walberla/walberla!44

added support for clang 5.0

See merge request !48