Implement methods for comparison of learners on a single task

[RaphaelS1]

Let's use this issue to collect ideas for methods/classes/functions for analysis of multiple learners on a single task.

[RaphaelS1]

https://jmlr.org/papers/v18/16-305.html

https://link.springer.com/article/10.1023%2FA%3A1024068626366

[pfistfl]

I am collecting existing implementations here:

• base (t.test, ...)
• https://cran.r-project.org/web/packages/scmamp/index.html
• https://github.com/rasmusab/bayesian_first_aid
• https://github.com/JacintoCC/rNPBST (java)
• https://cran.r-project.org/web/packages/PMCMRplus/vignettes/QuickReferenceGuide.html