Format and few fixes

examples/main.c

src/chemistry/EAGLE/chemistry_io.h

src/chemistry/GEAR/chemistry_io.h

src/common_io.c

src/common_io.h

src/gravity/Default/gravity_io.h

src/hydro/Default/hydro_io.h

src/hydro/Gadget2/hydro_io.h

src/hydro/GizmoMFM/hydro_io.h

src/hydro/Minimal/hydro_io.h

src/hydro/PressureEntropy/hydro_io.h

src/io_properties.h

src/stars/Default/star_io.h