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/stockit/index.html.haml

@@ -23,5 +23,5 @@
           %td=h article.name
           %td= article.quantity
           %td= article.unit
-          %td= article.net_price
+          %td= article.price
           %td= link_to article.supplier.name, article.supplier