No more timezone referenced in ical. Should resolve #76

app/views/events/index.ics.erb

 BEGIN:VCALENDAR
 VERSION:2.0
 PRODID:-//AgendaDuLibre.org
-X-WR-CALNAME:Agenda du Libre
-X-WR-TIMEZONE:Europe/Paris
-CALSCALE:GREGORIAN
-X-WR-CALDESC:<%= t 'title', scope: [:layouts, :application] %>
+X-WR-CALNAME:<%= t('title', scope: [:layouts, :application]).gsub(/'/, '’') %>
+X-WR-CALDESC:<%= t 'subtitle', scope: [:layouts, :application] %>
 <% @events.find_each do |event| %>
 BEGIN:VEVENT
 DTSTART:<%= event.start_time.strftime '%Y%m%dT%H%M%S' %>