* Removed jekyll-feed plugin -- it only works on posts, EIPs are created as pages
* Edited Last Call feed to work, and to have a header with EIP metadata in the RSS feed, including the discussion-to or Github issue link
This adds Twitter Card metadata to the site, using the format that
[`jekyll-seo-tag`](https://github.com/jekyll/jekyll-seo-tag/blob/master/docs/usage.md),
a dependency of Minima, understands. This should make the site render better
on Twitter.
I tested this locally and it seemed to work.