Filter a feed's items based on their title.
USAGE:
<original_feed.xml >filtered_feed.xml (rss|atom)_filter_title.py word...
<original_feed.xml >filtered_feed.xml (rss|atom)_filter_title.py --whitelist word...
The word arguments are a list of substrings that either must not
appear (default) or must appear (--whitelist) in the titles of the
output.
There are two variants of the script. rss_filter_title.py works on
RSS feeds while atom_filter_title.py works on ATOM
feeds.