Implement consistent admin interface

* Consistent route/model/controller/view layout
* Get rid of unused photos, speakers, dietchoices, social_events controllers
* Drop unused :public from Rooms and :description from CallForPapers

app/views/admin/tickets/_form.html.haml

@@ -1,5 +1,17 @@
-= f.input :title
-= f.input :description, input_html: { rows: 5, data: { provide: "markdown-editable" } }
-= f.input :price
-= f.input :price_currency, as: :select, class: 'form-control', collection: ['USD', 'EUR', 'GBP', 'INR', 'CNY'], include_blank: false
-= f.action :submit, as: :button, button_html: { class: 'btn btn-primary' }
+.row
+  .col-md-12
+    .page-header
+      %h1
+        - if @ticket.new_record?
+          New
+        = @ticket.title
+        Ticket
+.row
+  .col-md-8
+    = semantic_form_for(@ticket, :url => (@ticket.new_record? ? admin_conference_tickets_path : admin_conference_ticket_path(@conference.short_title, @ticket))) do |f|
+      = f.input :title
+      = f.input :description, input_html: { rows: 5, data: { provide: "markdown-editable" } }
+      = f.input :price
+      = f.input :price_currency, as: :select, class: 'form-control', collection: ['USD', 'EUR', 'GBP', 'INR', 'CNY'], include_blank: false
+      %p.text-right
+        = f.action :submit, as: :button, button_html: { class: 'btn btn-primary' }