add another constructor for subtyping

Sorting/WordQuickSorter.java

@@ -6,6 +6,10 @@ public class WordQuickSorter extends Sorter{
         super("quick sort", reader);
     }
 
+    public WordQuickSorter(String type, RandomWordFileReader reader) {
+        super(type, reader);
+    }
+
     void sort() {
         quicksort(0, words.length-1);
     }