Complete refactoring of orders-workflow.

OrderResult tables are removed. Data consistency is now possible through new article.price-history (ArticlePrice).
Balancing-workflow needs to be updated.

app/views/orders/edit.html.haml

@@ -1,7 +1,7 @@
 - title _("Edit order")
 
-- form_tag :action => 'update', :id => @order do
-  = render :partial => 'form'
+- form_for @order do |form|
+  = render :partial => 'form', :locals => { :form => form }
   = submit_tag _("Save")
   |
   = link_to _("Cancel"), :action => 'show', :id => @order