Merge pull request #42 from ov7a/patch-1

Non-zero exit code on error. Fixes #41

jplag/src/main/java/jplag/JPlag.java

@@ -17,6 +17,7 @@ public class JPlag {
             }
             catch(ExitException ex) {
                 System.out.println("Error: "+ex.getReport());
+		System.exit(1);
             }
 		}
 	}