Add py33 and pypy to tox.ini
diff --git a/tox.ini b/tox.ini
index 3c1bd57..6dd6c05 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist=py24,py25,py26,py27,py31,py32
+envlist=py24,py25,py26,py27,py31,py32,py33,pypy
 indexserver=
     default = http://pypi.python.org/simple
     testrun = http://pypi.testrun.org