Merge branch 'develop' of https://www.graphics.rwth-aachen.de:9000/ptrettner/polymesh into develop

.clang-format

.gitignore

CMakeLists.txt

Readme.md

cmake/SourceGroup.cmake

cmake/UnityBuild.cmake

docs/.gitignore

docs/Doxyfile

docs/Makefile

docs/attributes.rst

docs/contributing.rst

docs/index.rst

docs/mesh-topology.rst

docs/misc.rst

docs/performance.rst

docs/reference.rst

docs/roadmap.rst

docs/smart-ranges.rst

docs/vector-math.rst

src/polymesh/Mesh.hh