Unused headers

The following headers are currently not used in Dumux itself. Please change the table to mark the headers for something else than "delete", if you think that they should be kept. Please do so before July 26.

header	delete	test
common/intrange.hh	X
discretization/basefvgridgeometry.hh	X
io/grid/cakegridcreator.hh	X
io/grid/subgridgridcreator.hh	X
material/binarycoefficients/h2o_ch4.hh		x

Edited Aug 28, 2019 by Katharina Heck