LRDOCS-620 Added documentation of the calendar portlet's export/import functionality for calendar events and resources
LRDOCS-624 Added information about the friendly URL to calendar events that's included in event invitation notification emails; this is useful because it allows users easy access to events' views in the calendar portlet so they can respond to event invitations
Merge pull request #592 from jrao/LRDOCS-317

http://issues.liferay.com/browse/LRDOCS-620