Log Message:
Updated py-dulwich to 0.16.1.

0.16.1	2016-12-25

 BUG FIXES

  * Fix python3 compatibility for dulwich.contrib.release_robot.
    (Jelmer Vernooij)

0.16.0	2016-12-24

 IMPROVEMENTS

  * Add support for worktrees. See `git-worktree(1)` and
    `gitrepository-layout(5)`. (Laurent Rineau)

  * Add support for `commondir` file in Git control
    directories. (Laurent Rineau)

  * Add support for passwords in HTTP URLs.
    (Jon Bain, Mika Mäenpää)

  * Add `release_robot` script to contrib,
    allowing easy finding of current version based on Git tags.
    (Mark Mikofski)

  * Add ``Blob.splitlines`` method.
    (Jelmer Vernooij)

 BUG FIXES

  * Fix ``porcelain.reset`` to respect the comittish argument.
    (Koen Martens)

  * Fix handling of ``Commit.tree`` being set to an actual
    tree object rather than a tree id. (Jelmer Vernooij)

  * Return remote refs from LocalGitClient.fetch_pack(),
    consistent with the documentation for that method.
    (#461, Jelmer Vernooij)

  * Fix handling of unknown URL schemes in get_transport_and_path.
    (#465, Jelmer Vernooij)