length array was too short for keeping the readlengths.

public/biopet-tools/src/main/scala/nl/lumc/sasc/biopet/tools/SeqStat.scala

@@ -130,7 +130,7 @@ object SeqStat extends ToolCommand {
       baseStats ++= mutable.ArrayBuffer.fill(record.length - baseStats.length)(BaseStat())
     }
 
-    if (readStats.lengths.length < record.length) {
+    if (readStats.lengths.length <= record.length) {
       readStats.lengths ++= mutable.ArrayBuffer.fill(record.length - readStats.lengths.length + 1)(0)
     }