rename 'label' to 'name'.

Warning : this commit require to rename some table column, but the
original Version file has been update.

If you do not care to loose your date, you may run :

```
php app/console doctrine:migrations:execute --down 20160318111334
php app/console doctrine:migrations:execute --up 20160318111334
php app/console doctrine:cache:metadata #(if you have a cache for
doctrine meta date)
```
close #20

Form/EventType.php

@@ -67,7 +67,7 @@ class EventType extends AbstractType
         }
                 
         $builder
-            ->add('label')
+            ->add('name')
             ->add(
                 'date',
                 'date',