Changes

Please see [http://www.google.com/support/calendar/bin/answer.py?hl=en&answer=99358#sunbird Google's support page]. It works very similar for Thunderbird/Lightning. Note that the support page has outdated URLs in some places, so also read [https://blog.mozilla.org/calendar/2013/09/google-is-changing-the-location-url-of-their-caldav-calendars/ this blog post about new CalDAV URLs].