add another insert type to VararyNode

alib2std/src/extensions/tree.hpp

@@ -372,6 +372,14 @@ public:
 		( * it )->parent = static_cast < Cast * > ( this );
 	}
+	typename std::vector < Data >::iterator insert ( typename std::vector < Data >::iterator it, Data d ) {
+		it = children.insert ( it, std::move ( d ) );
+
+		( * std::prev ( it ) ) -> parent = static_cast < Cast * > ( this );
+
+		return it;
+	}
+
 	template < class InputIterator >
 	typename std::vector < Data >::iterator insert ( typename std::vector < Data >::iterator it, InputIterator first, InputIterator last ) {
 		size_t off = it - children.begin ( );
@@ -453,6 +461,10 @@ public:
 		const_cast < VararyNode < Data, ConstData, Cast > & > ( node ).setChild ( std::move ( child ), it );
 	}
+	typename std::vector < Data >::iterator insert ( const VararyNode < Data, ConstData, Cast > & node, typename std::vector < Data >::iterator it, Data child ) {
+		const_cast < VararyNode < Data, ConstData, Cast > & > ( node ).insert ( it, std::move ( child ) );
+	}
+
 	template < class InputIterator >
 	typename std::vector < Data >::iterator insert ( const VararyNode < Data, ConstData, Cast > & node, typename std::vector < Data >::iterator it, InputIterator first, InputIterator last ) {
 		const_cast < VararyNode < Data, ConstData, Cast > & > ( node ).insert ( it, first, last );