LCG_95 Update, master branch (2019.04.12.)

This mr finally updates all projects in the repository to use LCG_95 by default. And, what was a bit more labour intensive, the MR updates all the externals built by AnalysisBaseExternals to be the same versions that the other project pick up from LCG_95.

I also fixed a few bugs along the way. (In the TBB build on macOS. See https://sft.its.cern.ch/jira/browse/ROOT-9678 for more details.)

By chance I also found that in !475 (merged) I forgot to update how the doc target uses atlas_build_run.sh. It's pretty independent from the rest of this MR, but it seemed simplest to fix here.