Fix bug #1661857 (switch from using meta feed to the new allcalendars feed)

- add support for new database schema for Calendars table (new columns: selfUrl, editUrl, alternateUrl, eventsUrl)
- add database upgrade code
- update Events.DELETE constant
- add Calendars Entity support

Change-Id: I040d153ce9ba15f77b582c083a79ea6e8e777535
3 files changed