added priority to default tree node factory.

Author: JavaSaBr

src/main/java/com/ss/editor/ui/control/tree/node/factory/impl/DefaultTreeNodeFactory.java

@@ -34,6 +34,8 @@
  */
 public class DefaultTreeNodeFactory implements TreeNodeFactory {
 
+    public static final int PRIORITY = 0;
+
     @Override
     @FxThread
     public <T, V extends TreeNode<T>> @Nullable V createFor(@Nullable final T element, final long objectId) {
@@ -72,4 +74,9 @@ public class DefaultTreeNodeFactory implements TreeNodeFactory {
 
         return null;
     }
+
+    @Override
+    public int getPriority() {
+        return PRIORITY;
+    }
 }