Merged and pushed to the private repo. Thanks for the review!

Looks good to me.

I finished the pull request. Could you have a look, please, Florian?

I'm fine with merging this, but I just merged issue625, which renames the
namespace Utils to utils, which will require some small changes (sorry).

I'll defer to Florian. :-) (IOW, please merge when the two of you are happy.)

I have started a branch for this issue. Can one of you guys have a look and 
tell me if you're ok with the function's signature, please?

https://bitbucket.org/jendrikseipp/downward/pull-requests/41

The Merge-and-shrink code repeats some references in multiple places. Should we 
add a new header merge_and_shrink/papers.h to avoid repetition?

I looked at the function and like it. Anyone want to assign this to themselves?

I guess the main part of the work is adapting the existing paper references in
the paper.

The CEGAR code (issue600) adds a function format_paper_reference() in 
cegar/additive_cartesian_heuristic.cc. We should move this function to a more 
central place and use it for formatting all paper references.