Merge branch 'master' into cosmology

examples/SmoothedMetallicity/getGlass.sh

examples/SmoothedMetallicity/makeIC.py

examples/SmoothedMetallicity/plotSolution.py

examples/SmoothedMetallicity/run.sh

examples/SmoothedMetallicity/smoothed_metallicity.yml

src/Makefile.am

src/cell.c

src/chemistry.h

src/chemistry/EAGLE/chemistry.h

src/chemistry/EAGLE/chemistry_iact.h

src/chemistry/gear/chemistry.h

src/chemistry/gear/chemistry_iact.h

src/chemistry/gear/chemistry_io.h

src/chemistry/gear/chemistry_struct.h

src/chemistry/none/chemistry.h

src/chemistry/none/chemistry_iact.h

src/runner.c

src/runner_doiact.h

tests/test125cells.c

tests/test27cells.c