fixed memory leak in Node<i_ThresholdNode>::next
fixed memory leak in Node<i_ThresholdNode>::next

psteinb/vigra,DaveRichmond-/vigra,psteinb/vigra,psteinb/vigra,psteinb/vigra,DaveRichmond-/vigra,psteinb/vigra,DaveRichmond-/vigra,psteinb/vigra,DaveRichmond-/vigra,DaveRichmond-/vigra,DaveRichmond-/vigra,DaveRichmond-/vigra,psteinb/vigra