Create local ui object per repository, so .hg/hgrc don't get mixed.
This is needed for hooks, but may be important for other settings, too.
Fixes issue113, also integrated push-hook-lock.sh as a test case for this.
#header#
<title>#repo|escape# Changelog</title>
<description>#repo|escape# Changelog</description>
#entries%changelogentry#
</channel>
</rss>