patch up rewrite rule so that index.php may not get rewritten to index.php?url=index.html, as it only wastes cycles.
(Even though it didn't happen on my install...anyways, the rewrite rule also only steps into effect if $serendipity['indexFile'] != 'index.php', we may want to create a conditional rule here.
use a better fix, I guess.
We may need to think if there are other areas apart from RSS feeds that
may get cached using appropriate last-modified headers. Most of the frontend
will fail though, as sidebars may server dynamic content.
* Use templates_c for caching remote rss feeds
* Do not call session_start() for RSS feeds to allow caching. If session_start
is called, it would put no-cache, ... headers and disable 304/Not Modified
operations. This is a possibly hazardrous change, we need to further
watch this. That's also the reason I won't backport the fix to 0.8