Allow sending tags as well as the selected URL

This required two changes:

1. in the QML view, the signal has been changed to url, var
2. the model directly outputs a QStringList for ease of use

src/model/danboorupostmodel.cpp

@@ -108,9 +108,8 @@ QVariant DanbooruPostModel::data(const QModelIndex &index, int role) const
             return post->rating();
         case TagRole:
         {
-            QVariant variant;
-            variant.setValue(post->tags());
-            return variant;
+            QStringList tagList = post->tags().toList();
+            return tagList;
         }
         default:
             return QVariant();