Merge branch 'fk/blame' into next

Merge branch 'fk/blame' into next

* fk/blame:
  blame: Rename detection (take 2)
  rev-lib: Make it easy to do rename tracking (take 2)
  Make it possible to not clobber object.util in sort_in_topological_order (take 2)
  Add git-imap-send, derived from isync 1.0.1.
  repack: prune loose objects when -d is given
  try_to_simplify_commit(): do not skip inspecting tree change at boundary.
  Fix t1200 test for breakage caused by removal of full-stop at the end of fast-forward message.
  Describe how to add extra mail header lines in mail generated by git-format-patch.
  Document the --attach flag.
  allow double click on current HEAD id after git-pull