DOC/RLS: Update release notes workflow. Help Needed!

First of all, congrats to everyone. This will be a huge and very exciting release. Be sure to have a beer sometime this week.

But...I need some major help on the release notes. Going to send out a note to the mailing list, but please look through `docs/source/release/version0.5.rst` and letting me know what I missed. Our CHANGES is woefully sparse, and I know I've missed some important contributions.

Going forward, we need to double our efforts to make sure PRs don't get merged without also touching docs/source/release as well (Myself very much included in this.).

If one of the sections that's still a stub is your contribution. Please consider posting a blurb in the discussion here (or better yet a PR against jseabold/whatsnew-tools). I'll do my best to provide links to the docs and examples, but you know better what you did than I did and you should be enthusiastic about advertising your work.

If you worked on something or remember something that needs to be added - a bug, feature, or API breakage. Please let me know. We now provide a full list of closed issues and bugs using the tools written by the IPython developers, so we don't need to be exhaustive here.