Bw-recipe-2016

* Merge [12: Fix TypeError during run](https://github.com/brightway-lca/bw_recipe_2016/pull/12). Thanks ChristinaKockel!
* Merge [9: Fix bug: IndexError: tuple index out of range](https://github.com/brightway-lca/bw_recipe_2016/pull/9). Thanks BenPortner!
* Merge [7: Bug fixes for importing ReCiPe 2016 impact categories into bw projects](https://github.com/brightway-lca/bw_recipe_2016/pull/7). Thanks juweya!
* Merge [5: Documentation fixes](https://github.com/brightway-lca/bw_recipe_2016/pull/5). Thanks lvandepaer!
* Fix [13: Remove psutil dependency](https://github.com/brightway-lca/bw_recipe_2016/issues/13)

* Support three different versions of ReCiPe
* Fix duplicate characterization factors by solving various problems in ecoinvent and the ReCiPe data
* Fix some matching bugs that caused duplicate CFs

* Added a weighted single score indicator

* `add_recipe_2016` not deletes ReCiPe before importing it
* Fix error with `match_cas_numbers` not following the given categories and subcategories
* Deleted duplicate air category in toxicity matching
* Fixed sign for water CFs

* Added more water categories to eutrophication
* Created aggregated ecosystems total endpoint methods
* Change handling of `iron` and `iron ore` in mineral resources

Initial release