updated proposed schema spreadsheet
metadata_schema: add new proposed spreadsheet columns
metadata_schema: write new columns to fields
metadata_schema: update proposed name mapping
metadata_schema: more work on importing new spreadsheet
metadata_schema: section descriptions no longer in spreadsheet
metadata_schema: Makefile: don't clobber output on error
metadata_schema: Makefile: clean up temp file on failure
metadata_schema: update record information fields
metadata_schema: update identification information
metadata_schema: add resource fields
metadata_schema: restore program_url
metadata_schema: french version of data_series_issue_identification
metadata_schema: restore supplemental_information
metadata_schema: additional identification information fields
metadata_schema: remaining identification information fields
metadata_schema: remove unused sections
metadata_schema: geospatial fields
metadata_schema: USian spelling of catalog
metadata_schema: enable subject and topic_category