def reload()
      self.clear
      self.concat File.read(event_file).split(/\r?\n/).map{|e| Event.new(e)}
    end
def reload()
      self.clear
      self.concat File.read(event_file).split(/\r?\n/).map{|e| Event.new(e)}
    end
Reload the events from the event file. Existing events are
 deleted first.