Several schedules in the backend && routes changed

- Introduce plural resources for Schedule in routes.rb
- Introduce #index and #create actions for ScheduleController
- Make it possible to set a schedule as selected_schedule

app/views/admin/schedules/show.html.haml

@@ -1,27 +0,0 @@
-.row
-  .col-md-12
-    .page-header
-      %h1 Schedule
-      %p.text-muted
-        Create the schedules for the conference
-
-.row
-  .col-md-2
-    .h4
-      Unscheduled events
-    .unscheduled-events
-  .col-md-10
-    %ul.nav.nav-tabs
-      - @dates.each do |date|
-        %li{ class: "#{ (@dates.first == date) ? 'active' : '' }"}
-          %a{ href: "##{date}" }
-            = date
-    .tab-content
-      - @dates.each do |date|
-        .tab-pane{ class: "#{ (@dates.first == date) ? 'active' : '' }", id: "#{date}" }
-          = render partial: 'day_tab', locals: { date: date }
-
-:javascript
-  $(document).ready( function() {
-    Schedule.loadEvents("#{@conference.short_title}", "#{@schedule_id}");
-  });