LCG_96b Updates, master branch (2020.03.02.)

This is a sibling of !625 (merged), cherry-picking the updates made for the 1.0 branch into master as well. Except for one change, which was already cherry-picked in !628 (merged).

Note that I updated the build of FastJet a bit to bring it in sync with the 1.0 branch. @ssnyder may want to keep an eye on this, when the update hits the master nightlies. (I did try to keep your patch intact Scott...)

Will not copy any long description here, see !625 (merged) for the details. 😉