function remove( node, index, parent ) {
	if ( parent ) {
		parent.children.splice( index, 1 );
		return index;
	}
}
Removes all visited nodes.

@private
@param {Node} node - reference node
@param {number} index - position of `node` in `parent`
@param {Node} parent - parent of `node`
@returns {number} next index to visit