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

DataFixtures/ORM/LoadParticipation.php

@@ -80,7 +80,7 @@ class LoadParticipation extends AbstractFixture implements OrderedFixtureInterfa
         for($i=0; $i<$expectedNumber; $i++) {
             $event = (new Event())
                   ->setDate($this->faker->dateTimeBetween('-2 years', '+6 months'))
-                  ->setLabel($this->faker->words(rand(2,4), true))
+                  ->setName($this->faker->words(rand(2,4), true))
                   ->setType($this->getReference(LoadEventTypes::$refs[array_rand(LoadEventTypes::$refs)]))
                   ->setCenter($center)
                   ->setCircle(