flow_mapper() and form_mapper() each provide output information per cell
of a dem file. This function takes the fill dem from flow_mapper() as well
as the length and weti dem files from form_mapper() and merges them
together into a complete dem file with all information. This file is saved
to the project folder.
merge_all(folder, out_format = NULL)Character. Folder with previous LITAP runs (i.e. where output
of flow_mapper() etc. are)
Character. Output format (rds or csv) that merged file should be saved as (if different from the rest; by default uses the format of the other LITAP output files)