- generalized PdfFieldPackInfo to be used with a stencil template
  argument instead of a LatticeModel
- PdfPackInfo now available from Python

Add image generation using a raytracer

See merge request walberla/walberla!89

Pe-Coupling Classes Splits

See merge request walberla/walberla!120

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 !119

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

Closes #59

See merge request !109

Resolve "get pe c++14 ready"

Closes #58

See merge request !108