Add calendar example.

An example of Calendar used with an SQL model to view events.

Change-Id: I54887dcedf4ea6bbb12c7c35fe968ff13821b696
Reviewed-by: Mitch Curtis <mitch.curtis@digia.com>
Correct Calendar's selectedDate documentation.

date => selectedDate

Change-Id: I5a1ad4a1d47fd72c5b98b8f821f071343140aa43
Reviewed-by: Mitch Curtis <mitch.curtis@digia.com>