add view for Searches with headers

Idea

 

We'd like to implement recent changes as a card. recent almost accomplishes this (using Recent Layout), the only thing missing is a change-like view that inserts headers with the date of each day's chunk of changes.

 

{{*all+by update|change_with_headers}}

 

Applies only to Searches and Pointers.

Renders items in change view.

Inserts headers above each day, e.g.: February 26, 2011

 

No headers if the sort is not by create or update.