Optimization suggested by Ray.

git-svn-id: https://samskivert.googlecode.com/svn/trunk@2267 6335cc39-0255-0410-8fd6-9bcaacd3b74c

src/java/com/samskivert/util/ObjectUtil.java

@@ -56,7 +56,7 @@ public class ObjectUtil
      */
     public static <T extends Comparable<? super T>> int compareTo (T left, T right)
     {
-        if (left == null && right == null) {
+        if (left == right) { // instances are both null or both the same instance
             return 0;
         } else if (left == null) {
             return -1;