[PATCH v2] transplant: use absolute_import

[timeless]

Ok, the conflicts are sufficiently bad that i can't do much w/o
waiting for clowncopter to merge into default.

here's an updated (registrar conflict) and split series:
https://bitbucket.org/timeless/mercurial-crew/commits/70a030e942f1a6b90d5170b9efc853667ccac999
https://bitbucket.org/timeless/mercurial-crew/commits/c5b5143c73493a54a1f5daf168c864528e45460f