Static home page feature.
Remove bottom border from "pages", leave it on "posts".

A new sass version has changed the CSS output inconsequentially.
Remove old MotorClient.open_sync() call from test.
Test static home page and default home page.
Add a "widget" syntax to our Markdown dialect.
Widget-rendering.
Fix recent-posts layout.
Dead code.
Recent-posts widget can filter by tag.
Don't show publication date on post summaries.