Add function to create a new root.

src/node.h

@@ -73,11 +73,8 @@ struct Iso_Node
     IsoDir *parent; /**< parent node, NULL for root */
 
     /*
-     * Pointers to the doubled linked list of children in a dir.
-     * It is a circular list where the last child points to the first
-     * and viceversa.
+     * Pointer to the linked list of children in a dir.
      */
-    IsoNode *prev;
     IsoNode *next;
 };
 
@@ -118,4 +115,6 @@ struct Iso_Dir_Iter
     IsoNode *pos;
 };
 
+int iso_node_new_root(IsoDir **root);
+
 #endif /*LIBISO_NODE_H_*/