Event image

[spoorun]

Allow creator or editor of an event to load an image (picture) that will be associated with the event.
This will appear in the stream, in the calendar and when editing or viewing the event.
This will make the calendar more effective (utilising visual memory and selection) and more enjoyable, contemporary, attractive, and intuitive to use.
In cases where there is a physical or digital poster associated with the event, it will also serve as an archive and capture information that might otherwise be lost or hard to convey.