.update-copyright.conf: Automate maintenance for AUTHORS

Use my external update-copyright package [1] to maintain the AUTHORS
file.  Don't maintain the copyright blurbs though, since this project
sticks to:

  Copyright (c) 2014 Docker.
  <Apache blurb>

and doesn't list the file's individual contributors.

[1]: http://pypi.python.org/pypi/update-copyright/
.mailmap: Standardize author names and addresses

The syntax is described in the MAPPING AUTHORS section of
git-shortlog(1).  I looked for oddities and obvious duplicates in the
list of all commit authors, and added entries here that looked
reasonable to me.  When someone used multiple email addresses, I've
chosen to standardize on whichever address they used for their last
commit.  I haven't contacted any of these folks to confirm my choices.
AUTHORS: Run update-copyright.py to update this from the Git history
Merge pull request #669 from wking/update-copyright

Automate maintenance for AUTHORS with update-copyright