Aggregator module improvements:

 + Added some a new theme fucntions to the aggregator to make it possible to
   theme the aggregator page.
 + Removed the <table> and much hardcoded CSS as well as theme("box")-es.
 + Added the aggregator's theme functions to Doxygen's themeable group.
 + Added breadcrumb trails to the aggregator pages.
 + Updated the core themes to take advantages of the improved themeability.

Screenshot:

 http://buytaert.net/temporary/aggregator-makeover.jpg