Merge branch 'master' into doself2-vectorisation

.gitignore

README

configure.ac

examples/Makefile.am

examples/main.c

src/Makefile.am

src/atomic.h

src/cache.h

src/cell.c

src/cell.h

src/drift.h

src/engine.c

src/engine.h

src/gravity.c

src/gravity/Default/gravity.h

src/gravity/Default/gravity_part.h

src/gravity_derivatives.h

src/gravity_properties.c

src/gravity_softened_derivatives.h

src/hydro/Default/hydro_part.h