Add a function to add posts to pools (unsure if it'll be ever used...)

src/libdanbooru/danboorupool.cpp

@@ -68,9 +68,9 @@ void DanbooruPool::addPosts(QList< int > posts)
     m_posts.append(posts);
 }
 
-void DanbooruPool::addPosts(QStringList posts)
+void DanbooruPool::addPosts(const QStringList& posts)
 {
-    foreach (QString post, posts) {
+    foreach (const QString& post, posts) {
         m_posts.append(post.toInt());
     }
 }