Rename-only changes no longer ignored

[justinfenn]

In some earlier releases, commits that only renamed a file (like when moving between directories) would not be considered. It looks like that has changed, and now I am seeing unexpected change timestamps for moved files.

I investigated a bit, and I think db89b20 may have introduced the change. It looks like the commit identified with diff_filter="r" in place might be replaced by some other commit now.

[timvink]

Thanks for finding this one! I found and fix the error in #195. Release soon!