* Increasing after_login max string size from 100 to 1000 to accomodate larger URLs.
* controller.Notebooks now takes (and stores) an https_url constructor parameter.
* New controller.Notebooks.updates() method to produce an updates RSS feed for a particular notebook.
* New controller.Notebooks.get_update_link() method to make a brief page with just a link for an updated note, referred to by the feed.
* Implemented views for the new RSS feed.
* Fixed bug in Rss_item's guid that caused newlines to be inserted before and after long URLs.
* Still need to unit test new controller code.