fixes

app/views/conference/schedule.xml.haml

@@ -6,7 +6,7 @@
     %start= @conference.start_date
     %end= @conference.end_date
     %days= (@conference.end_date - @conference.start_date).to_i + 1
-    %timeslot_duration= '00:15' #FIXME
+    %timeslot_duration= length_timestamp(EventType::LENGTH_STEP)
 
   - if @events_xml.any?
     - @events_xml.keys.each.with_index(1) do |day, index|
@@ -18,7 +18,7 @@
               %event{ guid: event.guid, id: event.id }
                 %date= event.start_time.iso8601
                 %start= event.start_time.strftime('%H:%M')
-                %duration= event.event_type.length_timestamp
+                %duration= length_timestamp(event.event_type.length)
                 %room= event.room.name
                 %type= event.event_type.name
                 %language= 'en' #FIXME