Make Tester package-private

It doesn't need to be public so it shouldn't be.

Author: KiARC

lib/src/main/java/com/katiearose/Tester.java

@@ -2,7 +2,7 @@
 
 import java.util.Arrays;
 
-public class Tester { // Kinda not a great test but better than nothing
+class Tester { // Kinda not a great test but better than nothing
   public static void main(String[] args) {
     distributionTest();
     stressTest();