Throw error whenever the arguments are not complete

biopet-extensions/src/main/scala/nl/lumc/sasc/biopet/extensions/clever/CleverFixVCF.scala

@@ -118,7 +118,7 @@ object CleverFixVCF extends ToolCommand {
    */
   def main(args: Array[String]): Unit = {
     val argsParser = new OptParser
-    val commandArgs: Args = argsParser.parse(args, Args()) getOrElse sys.exit(1)
+    val commandArgs: Args = argsParser.parse(args, Args()) getOrElse(throw new IllegalArgumentException)
 
     val input: File = commandArgs.inputVCF
     val output: File = commandArgs.outputVCF