Miscellaneous:
* Correct the description of --force in git-debpush(1) [Sean Whitton].
* git-debrebase(*): fix some crossreferences [Sean Whitton].
- Closes#932536.
* Break out git-playtree-setup and rewrite in shell.
+ Closes:#932536.
* Fix organisation copyright attribution for Matthew Vernon's
contributions. Closes:#932630.
* HACKING: new document for helping people work on the code.