Splitting rpg module into several game modules.
rpg_tests -> game_tests
rpg_tests -> game_tests, fixing import paths.
Fixing the mean of d20 opposed tests.

(in unittests)
Reorganizing min and max, median is to be fixed.
Adding risk module.
Handling artifacts outside of scope.
Introduce mask in pmf bar plots.
Mask in risk attacks.
Fixing HarnMaster.
Cleaning a debug message.