specifying eval-label-file argument causes index out of bounds exception

[delip]

command line args to reproduce

-e examples/minimal/edges.minimal.tsv  -i 10 -o examples/minimal/predictions.tsv -s examples/minimal/seed_labels.minimal.tsv -t -v --eval-label-file examples/minimal/reference.output_predictions.minimal.csv

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 1
	at junto.graph.package$$anonfun$getLabels$2.apply(package.scala:48)
	at junto.graph.package$$anonfun$getLabels$2.apply(package.scala:44)
	at scala.collection.Iterator$$anon$11.next(Iterator.scala:409)
	at scala.collection.Iterator$$anon$13.hasNext(Iterator.scala:462)
	at scala.collection.Iterator$$anon$11.hasNext(Iterator.scala:408)
	at scala.collection.Iterator$class.foreach(Iterator.scala:893)
	at scala.collection.AbstractIterator.foreach(Iterator.scala:1336)
	at scala.collection.TraversableOnce$class.toMap(TraversableOnce.scala:316)
	at scala.collection.AbstractIterator.toMap(Iterator.scala:1336)
	at junto.Junto$.main(Junto.scala:36)
	at junto.Junto.main(Junto.scala)