* Allow notifications to include media, with Twitter as the first implementation. The Twitter notifier uses the Twitter-recommended async chunked media/upload approach and tries to convey the correct mime type of the media. Twitter implementation based on https://github.com/geduldig/TwitterAPI/blob/master/examples/upload_video.py.
* Changes based on balloob's review:
balloob: "Please remove this file. We fixed the issue in our tests that left this artifact."
balloob: "…prefer a guard clause"
balloob: "This is very inefficient. You are now generating up to 99 values."
balloob: "Since media_id is going to be None, why not just return None and you can remove the else."
* balloob: "Other notify platforms are using ATTR_DATA for it. That way if a platform requires extra metadata, we don't need to add extra fields. So please add it to Twitter via ATTR_DATA."
Mike Christianson
92dc76773a