doc: langevin: field file format and small changes
doc: langevin-tm: output format and small changes
doc: strings for -h revised, default output files
fix for default output file of langevin-tm

unused code deleted and .ltm suffix
doc: default output file (last changes); cosmetics
doc: take back wrong change on -F
doc: -h: default all input data

in analogy to langevin-tm.c
doc: typo