/all becomes tag page latest for fronts

![datelinks](https://cloud.githubusercontent.com/assets/1001642/5090658/98e56ad6-6f3b-11e4-8206-3087aa18b34d.gif)

This repurposes /all. It now provides the 'index' view (i.e., the default view for a tag page / front) for a front, allowing you to paginate backwards for content on sections like 'sport'.

Containers that represent a single day now also link through to that day's permanent URL, allowing Google to discover and index these pages.

Next:

* Add a link from a front to the corresponding 'all' page if it is actually a tag or section
* Create an endpoint for a view of a particular month, making those also easily discoverable. (This view is also going to be useful in the future for a special project SHHH!)