Utilities and Extensions to the geometry functionality

See merge request walberla/walberla!117

Utilities and functionalities for AMR and LB

See merge request walberla/walberla!116

# Conflicts:
#   tests/pe_coupling/CMakeLists.txt

Implementation changes pecoupling module

See merge request walberla/walberla!118

Added functionality to timers and fixed docu typos

See merge request walberla/walberla!115

Resolve "Conversion warnings after pe C++14 adaptions"

Closes #64

See merge request walberla/walberla!119

Resolve "std::array support for send / recv buffer shift operators"

Closes #59

See merge request walberla/walberla!109

Resolve "get pe c++14 ready"

Closes #58

See merge request walberla/walberla!108

using smart pointers instead