added TimeZone capabilities

When it's necessary to create an event at a specific date / hour and place ( with Timezone)

i.e
        time_zone =  place.geolocation[:time_zone]  #  =>  "Europe/London"
        tod = TimeOfDay.new 9, 30
        start_date = tod.on(Date.today, time_zone)
        tod = TimeOfDay.new 22, 00
        end_date = tod.on(Date.today, time_zone)
        event = FactoryGirl.create(:event, place: place, title: "My New Event",  starts_at: start_date, ends_at: end_date