Show event time in conference timezone

Added an application helper method `time_with_timezone` to return time with the conference timezone which solves the issue of wrong timezone in `scheule.xml` and `admin/events#show`.

Fixes #1188

app/helpers/application_helper.rb

@@ -34,6 +34,11 @@ module ApplicationHelper
     result
   end
 
+  # Returns time with conference timezone
+  def time_with_timezone(time)
+    time.strftime('%F %R') + ' ' + @conference.timezone.to_s
+  end
+
   ##
   # Checks if the voting has already started, or if it has already ended
   #

app/views/admin/events/_proposal.html.haml

@@ -117,7 +117,7 @@
           %td
             %b Scheduled time
           %td
-            = @event.time
+            = time_with_timezone(@event.time)
       %tr
         %td
           %b Submitter

app/views/schedules/show.xml.haml

@@ -16,7 +16,7 @@
           %room{ name: room.name }
             - events_in_rooms[room].each do |event|
               %event{ guid: event.guid, id: event.id }
-                %date= event.time.iso8601
+                %date= time_with_timezone(event.time)
                 %start= event.time.strftime('%H:%M')
                 %duration= length_timestamp(event.event_type.length)
                 %room= event.room.name