Merge branch 'cpp' into 'master'

INSTALL.swift

configure.ac

examples/main.c

src/align.h

src/atomic.h

src/clocks.c

src/common_io.c

src/common_io.h

src/engine.c

src/gravity_cache.h

src/hydro_space.c

src/inline.h

src/io_properties.h

src/logger.c

src/parallel_io.c

src/parser.c

src/partition.c

src/proxy.c

src/restart.c

src/runner.c