Added sitemaps.org schema for edition page.
Send mail to person checked out the book only if people are waiting.
Don't send emails until 2 days after borrowing the book.
Bumped the number of available books.
Ignore bad years when plotting publishing history.
fix
Added banner for edition pages that can be read-online or borrowed.
minor changes
Fix URLs included in emails when the email is triggered from a script.

Looks like the default host name is '[unknown]' for whatever reason.
Added a check to use "http://openlibrary.org" when web.ctx.home contains
"[unknown]".
cleanup. deleted some unused code.
cache blog feeds in memcache.

It is a bad idea to cache stuff in process memory.
updated the update-loans.py script to update both loans and waitinglists