Merge branch 'master' of http://gitlab.mpcdf.mpg.de/vrs/gadget4

Template-Config.sh

defines_extra

documentation/04_config-options.md

src/data/constants.h

src/data/simparticles.h

src/domain/domain.h

src/domain/domain_box.cc

src/io/snap_io.cc

src/io/snap_io.h

src/main/init.cc

src/main/run.cc

src/sph/density.cc

src/subfind/subfind_density.cc

src/subfind/subfind_findlinkngb.cc

src/subfind/subfind_nearesttwo.cc

src/time_integration/kicks.cc