Django-bulbs

- Added animated gif support to the instant article renderer & parser

- Added twitter video parsing
- Parser checks `src` on youtube iframe embeds

- Added [`ReportBugEmail`](https://github.com/theonion/django-bulbs/blob/4034cb55ec4142d022bf8b48fa71cd935dc473db/bulbs/api/views.pyL608-L638) view for a common bug reporter endpoint

- Added `<blockquote>`, `<ol>`, `<ul>`, `<h3>`, and `<h4>` support to instant article parser
- Added in `content.subhead` to `base_instant_article.html`

- Added `parser.py`, which parses article bodies, and sends them to `renderer.py`, which can render article bodies in a particular format
- Update `base_instant_article.html` and `base_instant_article_rss.xml` to use generated body, based on `parser.py` & `renderer.py`

- Move special coverage styles into bulbs styles