Evolution #774: Savoir si piste déjà présente dans playlist

app/Resources/translations/elements.fr.yml

   create_submit:         Ajouter
   public_label:          Rendre cette liste publique
   public_word:           (publique)
+  contained:             La musique est déjà présente dans cette liste
+  not_contained:             La musique n'est pas présente dans cette liste

src/Muzich/CoreBundle/Entity/Playlist.php

     return $elements_manager->have($element);
   }
   
+  public function haveElementId($element_id)
+  {
+    $elements_manager = new ElementCollectionManager(json_decode($this->elements, true));
+    return $elements_manager->haveRefId($element_id);
+  }
+  
   public function setCopied(Playlist $copied)
   {
     $this->copied = $copied;

src/Muzich/CoreBundle/Resources/public/css/main.css

   margin-top: 2px;
 }
 
+ul.playlists_for_element
+{
+  margin-left: 28px;
+  margin-top: 8px;
+}
+
+ul.playlists_for_element li
+{
+  list-style-image: url(/img/notin.png);
+}
+
+ul.playlists_for_element li.in
+{
+  list-style-image: url(/img/in.png);
+}
+
 /*
 *
 *

src/Muzich/CoreBundle/lib/Collection/CollectionManager.php

     return false;
   }
   
+  public function haveRefId($ref_id)
+  {
+    foreach ($this->content as $content_line)
+    {
+      if ($ref_id == $content_line[lcfirst($this->object_reference_attribute)])
+      {
+        return true;
+      }
+    }
+    
+    return false;
+  }
+  
   public function remove($object)
   {
     $new_content = array();

src/Muzich/PlaylistBundle/Resources/views/Show/prompt.html.twig

     <h2>{{ 'playlist.add_to'|trans({}, 'elements') }}</h2>
     <ul class="playlists_for_element">
       {% for playlist in playlists %}
-        <li class="playlist">
+        <li
+          class="playlist {% if playlist.haveElementId(element_id) %}in{% endif %}"
+          title="{% if playlist.haveElementId(element_id) %}{{ 'playlist.contained'|trans({}, 'elements') }}{% else %}{{ 'playlist.not_contained'|trans({}, 'elements') }}{% endif %}"
+        >
           <a class="add_element_to_playlist"
             {% if playlist.owned(app.user) %}
               href="{{ path_token('playlists_add_element', {