Trade data from BACI to-be-used with regioinvent.

The dataset contains import and export data of traded goods corresponding to ecoinvent products from the BACI database (https://www.cepii.fr/CEPII/en/bdd_modele/bdd_modele_item.asp?id=37), as well as production data from FAOSTAT and BGS/USGS and data used to estimation total production volumes from EXIOBASEv3.9.5. The only purpose of this dataset is to be used as an input to the Regioinvent Python package which can be found here: https://github.com/CIRAIG/Regioinvent v4 changes: Complete structure changed to accomodate for implementation of real production volume data, instead of only relying on the estimates from EXIOBASE. Also, now uses net exports to avoid problems wit re-exports. Imports were corrected in consequence to function be consistent with net exports.