[churn] Ignore merge csets Merge changesets attributed a large number of lines to people that didn't actually develop it, but simply merged the code. By ignoring merges, we get a more accurate picture of how much code everyone changed.

<item>
    <title>#tag|escape#</title>
    <link>#url#?cs=#node|short#</link>
    <description><![CDATA[#tag|strip|escape|addbreaks#]]></description>
    <pubDate>#date|rfc822date#</pubDate>
</item>