Add support for React 0.13. Switch from 6to5 to Babel.

[kloots]

No description provided.

[AsaAyers]

@kloots and @angus-c Since you both seem to be collaborators could one of you take a look at these PRs? If you merge them they'll close a bunch of other issue but I've never been able to get a response from anyone with merge access. I had to make a fork so I can use this project: @asaayers/react-a11y

	Description	Age
#14	Mark all failing tags with an ID and include it in the message	70 days old
#15	[fixed] Button role didn't allow onKeyDown	67 days old
#22	[fixed] tabIndex={0}	32 days old
#24	Drop React from peerDependency and rely on passing it in.	25 days old