Merge branch 'master' into JB_noncompatible

Conflicts:
	src/coupling/equation.cc
	src/coupling/equation.hh
	src/fields/field_interpolated_p0_impl.hh
	src/flow/darcy_flow_mh.cc
	src/input/accessors.hh
	src/mesh/mesh.cc
	src/mesh/ngh/src/intersection.cpp
	src/mesh/ngh/src/tetrahedron.cpp
	src/system/exceptions.hh