Updated to pybench 2.0.

See svn.python.org/external/pybench-2.0 for the original import of that
version.

Note that platform.py was not copied over from pybench-2.0 since
it is already part of Python 2.5.
diff --git a/Tools/pybench/Instances.py b/Tools/pybench/Instances.py
index 9b1929d..1dfc82f 100644
--- a/Tools/pybench/Instances.py
+++ b/Tools/pybench/Instances.py
@@ -2,9 +2,9 @@
 
 class CreateInstances(Test):
 
-    version = 0.2
+    version = 2.0
     operations = 3 + 7 + 4
-    rounds = 60000
+    rounds = 80000
 
     def test(self):