No, but that is probably because such a thing hasn't ever really been needed. To be a reasonably good product, it would probably need to parse the language to show both an actual pixel-for-pixel difference and a what-is-practically-different diff. Merging seems next to impossible with more complex programs, unless there could be an art->program->art program. The problem with that is that it would (probably) destroy any comment art or organization that was in the program before. The more I think about it, the more I think that a merge for this sort of file would be a really cool semester project for a comp sci class.