Oauth-dropins

Notable changes
Mostly just internal changes to webutil to support granary v1.9.

* Flickr:
* Handle punctuation in error messages.

Notable changes
* Facebook:
* Upgrade Graph API from v2.6 to v2.10.
* Flickr:
* Fix broken `FlickrAuth.urlopen()` method.
* Medium:
* Bug fix for Medium OAuth callback error handling.
* IndieAuth:
* Store authorization endpoint in state instead of rediscovering it from `me` parameter, [which is going away](https://github.com/aaronpk/IndieAuth.com/issues/167).

Notable changes

Updates to bundled webutil library, notably WideUnicode class.

Notable changes
- Add auto-generated docs with Sphinx. Published at https://oauth-dropins.readthedocs.io/
- Fix Dropbox bug with fetching access token.

Notable changes
- Add Medium.

Notable changes
- Upgrade Facebook API from v2.2 to v2.6.