Add BAT, 1.0 branch (2017.06.20.)
This is my own take on building Bayesian Analysis Tools as part of the analysis release, based on @iconnell's !50 (closed). I just cleaned up a few things from his MR that I didn't like.
Plus, I set this up on top of the 1.0 branch, as this should be the primary target for this code.
Tested on both SLC6 and MacOS, it seems to work fine.