csvs.py: Added tsv_encode_map for use in creating TSVs parsed by TsvReader

csvs.py: TsvReader: Also interpret '\t' as a tab, to provide a mechanism for encoding embedded tabs

tnrs.py: gwt_encode(): Escape special characters in the string instead of removing them, so that TNRS receives the original name rather than a modified version. This will help make the submitted names match up with the returned Name_submitted.

strings.py: Added json_encode()

strings.py: Added esc_quotes()

schemas/vegbien.sql: placepath.canon_placepath_id: Changed hierarchy comment to match the taxonpath.canon_taxonpath_id comment, but with a two-level hierarchy of datasource name -> accepted name. This may later be changed to a three-level hierarchy like taxonpath.canon_taxonpath_id depending on how GNRS works.

schemas/vegbien.sql: taxonpath.canon_taxonpath_id: Changed comment to specify that taxonpaths should now be linked in a three-level hierarchy of datasource name -> concatenated name -> accepted name

schemas/vegbien.sql: taxonpath, placepath: Changed "scrubbed" to "accepted" to emphasize that the name is the accepted name returned by TNRS or GNRS, rather than merely the matched name

mappings/VegCore-VegBIEN.csv: non-TNRS taxonpaths: Store the concatenated identifyingtaxonomicname in a separate taxonpath owned by the TNRS datasource, so that it will match up with (and create a link to) the corresponding submitted TNRS name's taxonpath. This in turn is linked to the TNRS-determined accepted name, thus creating a three-level hierarchy of datasource name -> concatenated name -> accepted name.

mappings/VegCore-VegBIEN.csv: taxonomic terms: Remapped the concatenated taxonomic name to new identifyingtaxonomicname to use it directly to match up with the TNRS submitted name. Continue to map scientificNameWithAuthorship to taxonomicnamewithauthor.