A series of [[Event]]s. Included events can relate with the series using the [[superEvent]] property.
An EventSeries is a collection of events that share some unifying characteristic. For example, "The Olympic Games" is a series, which
is repeated regularly. The "2012 London Olympics" can be presented both as an [[Event]] in the series "Olympic Games", and as an
[[EventSeries]] that included a number of sporting competitions as Events.
The nature of the association between the events in an [[EventSeries]] can vary, but typical examples could
include a thematic event series (e.g. topical meetups or classes), or a series of regular events that share a location, attendee group and/or organizers.
EventSeries has been defined as a kind of Event to make it easy for publishers to use it in an Event context without
worrying about which kinds of series are really event-like enough to call an Event. In general an EventSeries
may seem more Event-like when the period of time is compact and when aspects such as location are fixed, but
it may also sometimes prove useful to describe a longer-term series as an Event.