Fixed issue 71, add atom feeds.

The basic building block is here with the feed of the timeline, it is
rather easy to add the feed other elements based on this work. This will
require iterations and polishing.

src/IDF/templates/idf/project/timeline.html

@@ -1,4 +1,5 @@
 {extends "idf/base.html"}
+{block extraheader}<link rel="alternate" type="application/atom+xml" title="{trans 'Latest updates'}" href="{$feedurl}"/>{/block}
 {block docclass}yui-t2{/block}
 {block tabhome} class="active"{/block}
 {block subtabs}