Figure out how to deal with changes on the data, which are not on a graph level
related to #13 (closed), second point.
Currently we do not generate a patch for these (and can not?). But this breaks the provenance of the patch stack, i,e one cannot get the uplifted data version from the patch stack.
one option would be to parse both input and output data as graphs and generate a patch, but then one needs special functionality for blank nodes?