Adds summary BEA tables for 2012-2016, 2012 Detail tables, and updated Gross Output data all in 2017 schema. (aligns with https://github.com/USEPA/useeior/pull/293)
Updates the GHG FBS for 2012-2016 to use a consistent approach with the more recent FBS (Supply Use tables in 2017 schema) for attribution. The 2012-2016 summary tables are disaggregated to detail based on the 2012 Detail tables.