* Media_RSS_Controller::$LIMIT is now self::$page_size
* We use ORM_MPTT descendant_counts()
* If the page is out of bounds, put it on a boundary
* Move pub_date into the controller to simplify the mrss file
* Put all the view assignment in one block for easier reading
* Removed stray ; from the end of lines in the mrss file
Clean up ORM_MPTT a bit:
* fix spelling: decendent -> descendant
* Remove unnecessary order_by() clauses
* Set the default for $type to null (not "all").
doesn't refer to a fixed resource or collection of resources.
Fix some minor bugs in the code so that we can actually generate a
feed. It looks pretty cool! Improved pagination links, but didn't actually test them.
1) added a mime_type property to the item module(no database change)
2) created a media_rss module
3) moved most of the functionality for the downloading the images to the media_rss module
