Restore old Commit#parents method. There is a bug with getting the parents of a Commit created by Commit.find_head, but it turns out to be independent from the implementation of Commit#parents.
Improve Repo#find: allows passing in type == :any (default). Make sure that the found RevObject is actually a RevBlob, if type == :blob, since blobs need to be found using the parse_any method (parse_blob does not exist).