Added schemas/vegbank.revised.sql. Initial version has all "character varying" types replaced with text.

vegbien.sql: Replaced all "character varying" types with text, removing the length limits. Note that in PostgreSQL, text and "character varying" are stored the same way internally, so this does not affect performance or indexes.

xml_dom.py: Added documentation labels to each section

xml_dom.py: Fixed bug in NodeTextEntryIter where an entry containing an element instead of a text node would be returned as the whole entry, instead of the value of the entry

bin/map: Added support for starting import at a specific row. Refactored row-processing code with and without a map to use a common process_rows() function (with the previous process_rows() being renamed to map_rows()).

bin/map: Use new util.cast()

util.py: Added cast() to cast a value while passing None through

bin/map: Print row # of rows with errors

sql.py: Fixed error in pkey() where recover was not passed as a named parameter to run_query()

sql.py: Added documentation labels to each section