Merge branch develop into branch develop_holger.

src/calc_res.c

src/check_recfile.c

src/fd.h

src/ifos3d.c

src/readrec.c

src/readseis.c

src/saveseis.c

src/savesig.c

src/stfi.c

src/stfi_apply.c

src/stfi_calc.c

src/stfi_merge.c

src/time_window.c

src/timeloop.c