New field for event images

[djphil]

Perhaps we could add a new field in the table ossearch_events ...
It would be interesting to have the possibility to add an image for the event.
Of course we can create a new table for that but maybee we can only add a new field ...

[djphil]

So, i made small modiffication in the Events table.
I added new field at the end (pictureUUID).
Working with uuid of the image seems to me a good solution.
This new field seems not to cause a new bug.
Everything works well to display events on a web page.
Screenshot: http://imgur.com/a/MeCcq