Fixing a findbugs warning. clone() is defined on this class but it didn't implement Cloneable.

git-svn-id: https://svn.apache.org/repos/asf/xalan/java/trunk@1225434 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/org/apache/xalan/xsltc/util/IntegerArray.java b/src/org/apache/xalan/xsltc/util/IntegerArray.java
index c4358d9..62c40fe 100644
--- a/src/org/apache/xalan/xsltc/util/IntegerArray.java
+++ b/src/org/apache/xalan/xsltc/util/IntegerArray.java
@@ -24,7 +24,7 @@
 /**
  * @author Jacek Ambroziak
  */
-public final class IntegerArray {
+public final class IntegerArray implements Cloneable {
     private static final int InitialSize = 32;
     
     private int[] _array;