Régis LEBRUN

### What happened? If I want to modify the colorbar location of a Contour once it has been put into a Graph, I don't have access to the Contour interface...

In this PR, you will find: * The CombinationDistribution class, the uniform distribution over the set of strictly increasing functions from {0,...,k-1} to {0,...,n-1} where k and n are natural...