This patch includes fixes to : 1) substantially increase the efficiency of summing the histograms when using the GPU; 2) Add validation the reweighting and check that caching used by CPU calculation correctly updates; and, 3) add a collection of quality of life fixes (particularly, fewer warnings during compilation).

Fixes relative to 1.8.3

Issue #545 : Make the handling of ROOT config information portable between linux and macos. This no longer assumes how ROOT is installed, and uses root-config safely.

Update (Related to #540): Strengthen the NaN trap in the JointProbability calculation. An NaN there means the fit cannot continue, so throw an error. Continue to allow INF.

Update (Prompted by #541): Make compilation less alarming by quieting warnings. They were originally part of debugging.

Issue #536 : Add control over the size of a "kick" when starting a fit. The starting point can be fluctuated around the prior, and the size of the step is controlled by an optional argument to --kickmc

Issue #534 : Backport CPU and GPU calculation backing from main, and add validation that the two calculations agree within machine precision.

Issue #530 : Fix an inefficiency in the summation of the event weights on the GPU and double the speed of the likelihood calculation using the GPU.

Issue # 524 : Apply the global event weight cap when using the Cache::Manager to calculate the likelihood.

Full Changelog: 1.8.3...1.8.4