diag option: diagnostic run does not run through with current Backbone version
When using the "--diag=yes" option, Backbone (dev, commit 6e761d35, 19.11.2020) does not finish and throws the error "Unknown identifier entered as set". The error points to 4b_outputInvariants.gms to line 599 (estimated efficiency). Here "fuel" is used instead of "commodity", also the term "uFuel" does not seem to exist anymore.