parse xml docs as pure xml again but set nodeid
to TAG_LINK etc. so Linkdb.cpp can get links again.
added isparentsitemap url filter to prioritize urls
from sitemaps. added isrssext to url filters to
prioritize new possible rss feed urls. added numinlinks
to url filters to prioritize popular urls for spidering.
use those filters in default web filter set.
fix filters that delete urls from the index using
the 'DELETE' priority. they weren't getting deleted.
