few improvements on article category

- add verbose names to ArticleCategory fields
- add button to view categories list from articles list
- fix article_update template in form validation
- improve interface for articlecategory_update
- revert vanished urls (happened in merge with master...)

kfet/urls.py

@@ -69,6 +69,12 @@ urlpatterns = [
         name='kfet.account.negative'),
 
     # Account - Statistics
+    url(r'^accounts/(?P<trigramme>.{3})/stat/operations/list$',
+        views.AccountStatOperationList.as_view(),
+        name='kfet.account.stat.operation.list'),
+    url(r'^accounts/(?P<trigramme>.{3})/stat/operations$',
+        views.AccountStatOperation.as_view(),
+        name='kfet.account.stat.operation'),
 
     url(r'^accounts/(?P<trigramme>.{3})/stat/balance/list$',
         views.AccountStatBalanceList.as_view(),