I've worked on the merging logic in a version managed database and merging structured data is not an easy problem, especially as consistent output options tend to lose more data than the user would like or expect, so you have to write intelligent merging routines that understand the datamodel at a pretty deep level. I haven't looked at this library yet, but if it does provide a merging framework then it will still require significant work in each app to produce good results.

For a more complex merge, you can take a look at the 'Branching' video, near the end, we show a merge between two branches in a graphics editor.

We also give a brief overview of the Diff/Merge model here: http://coreobject.org/technotes/#diffmerge