Added mesh module

CMakeLists.txt

apps/benchmarks/CMakeLists.txt

apps/benchmarks/ComplexGeometry/CMakeLists.txt

apps/benchmarks/ComplexGeometry/ComplexGeometry.cpp

apps/benchmarks/ComplexGeometry/bunny.obj

apps/benchmarks/ComplexGeometry/cube.obj

apps/benchmarks/ComplexGeometry/input.conf

apps/benchmarks/ComplexGeometry/sphere.obj

apps/benchmarks/ComplexGeometry/test.conf

apps/benchmarks/MeshDistance/CMakeLists.txt

apps/benchmarks/MeshDistance/MeshDistanceBenchmark.cpp

apps/benchmarks/MeshDistance/bunny.obj

apps/pythonmodule/CMakeLists.txt

apps/pythonmodule/PythonModule.cpp

cmake/waLBerlaFunctions.cmake

doc/pics/mesh/triangle_topo.svg

doc/walberla.bib

src/geometry/all.h

src/geometry/containment_octree/BranchNode.h

src/geometry/containment_octree/ContainmentOctree.h