Visualize inclusion probabilities over all papers.

[mmantyla]

For large bodies of papers it would be useful to see such a graph where we see the shape of inclusion probability over all paper.

This would be useful in the preliminary evaluation phase of whether and how papers would get included to a review.

Also would be helpful in formulating the inclusion and exclusion criteria. The criteria should not be too but not too lose either as one end you have too few papers and in the other one too many.

We could even plot each criteria as separate line.

Thanks @jnyyssol for the idea.