* HTML docs with demos
* Limit input feeds via regex or to feeds listed in an OPML file.

* Tighten up between-item whitespace left behind when items filtered out of the feed

* Cache individual transformations keyed on item ID, so as not to keep altering the same item.

* Cross-format converter
* Feed content sanitizer - simplify HTML content, filter out potential scripting exploits
* Feed repair kit - use Magpie & etc to read in broken feed, do best to rebuild valid feed
* Support XSL transformations
* Blend multiple feeds into a master templated feed

* Improve self-documenting facets of commands
* Abstract $_GET away from commands, facilitate presence in chains of other filters
* Create a 'composer' for filters, allowing filter chain construction within an AJAX-y UI

Extracted TODO's
================

./includes/FeedMagick/ExtractingSaxFeedFilter.php:50:            // TODO: Handle @href on links in Atom
./includes/FeedMagick/ExtractingSaxFeedFilter.php:51:            // TODO: Handle author/name in Atom
./includes/FeedMagick/XMLGeneratorFilter.php:43:            // TODO: Need to build a proper XML declaration here with respect to encoding, charset
./includes/FeedMagick/XMLGeneratorFilter.php:67:            // TODO: Not sure about the parameters of namespace end handler.
./includes/XML/SaxFilters/ExpatParser.php:59:        // TODO: Find a proper fix for using a namespace-aware parser.
./includes/HTTPCache.php:101:                // TODO: Streamline this age check into the 304 check below?
./includes/HTTPCache.php:165:            // TODO: Report error if HTTPCache cache file not writable
./includes/common.php:64:                // TODO: Send off an application/rss+xml header?
./www-bin/alias.php:36:        // TODO: Report error if problem loading up record
./www-bin/alias.php:51:            // TODO: Is using the Location: header really the best way to handle the aliases?
./www-bin/alias.php:60:            // TODO: Determine if these are sufficient headers for passthru
./www-bin/alias.php:103:        // TODO: Report error if file not writable
./www-bin/technorati-related.php:7:    // TODO: Need to use an actual Technorati API wrapper
./www-bin/technorati-related.php:8:    // TODO: Needs caching on Technorati API searches
./www-bin/technorati-related.php:9:    // TODO: Better xpath handling in DOM, some pre-processing in DOMFeedFilter?
./www-bin/alter-feed-header.php:47:            // TODO: Make this work with attributes, not just container elements.
./www-bin/alter-feed-header.php:48:            // TODO: If nodes not found, provide option to create new node.
./www-bin/summarize-feed.php:12:        // TODO: Support stripping tags altogether (ie. content:encoded, atom:content)
./www-bin/summarize-feed.php:13:        // TODO: Not quite handling content:encoded properly
./www-bin/summarize-feed.php:14:        // TODO: Not quite handling Atom type="text/html", should change to text/plain?
./www-bin/summarize-feed.php:15:        // TODO: Would this be better off as a DOM-based filter?
./www-bin/stylesheet-adder.php:20:            // TODO: Find a better way to insert the stylesheet directive than splitting on "\n" and looking for <?xml version
./xsl/rss.xsl:4:        TODO: Don't steal this XSL entirely from the BBC.