Merge branch 'select_io' into 'master'

.gitignore

configure.ac

examples/SedovBlast_3D/sedov.yml

examples/main.c

src/chemistry/EAGLE/chemistry_io.h

src/chemistry/GEAR/chemistry_io.h

src/chemistry/none/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/GizmoMFV/hydro_io.h

src/hydro/Minimal/hydro_io.h

src/hydro/MinimalMultiMat/hydro_io.h

src/hydro/PressureEnergy/hydro_io.h

src/hydro/PressureEntropy/hydro_io.h

src/hydro/Shadowswift/hydro_io.h

src/parallel_io.c