utf-8 decode error while running humann_join_tables: reading hidden files on osx

This bug was discovered while attempting to merge the pathabundance.tsv tables in humann3; pathcoverage and genefamilies tables merged without issue. While investigating which file was being read at the time of the error, it was discovered that the script was reading from a ‘.XXXX’ file, which was not utf-8 unicode and triggered the error. These hidden temp files should be instructed to be removed upon completion of humann to avoid this downstream issue, or the scripts to be instructed to ignore hidden files (e.g.: '.’ prefixes).

Thanks for bringing this to our attention - we’ll add it to our HUMAnN development list.