OpenSSL TSE Causal Analysis Feature Transformations

[carlosparadis]

A number of variable transformations are required for causal analysis. Will use this issue and paired branch to revise this code into Kaiaulu over time.

[carlosparadis]

I decided to move any causal efforts to a separate package, Kumu: https://github.com/sailuh/kumu, including an interface to Tetrad and the various feature transformations required for causal analysis.