Revert "Merge remote-tracking branch 'original/interacting-solvers' into interacting-solvers"

This reverts commit 8dcaf813cd6aa7f128584d9f746b34da543598de, reversing
changes made to e78e861217376d2a3ed595eefdd81f5d04da10d9.
Added graph coloring example
Merge branch 'interacting-solvers' of github.com:codeZeilen/babelsberg-r into HEAD