add note that this is not a polyfill

tj · tj · commit 0e8f64c3f0bb · 2012-09-16T20:42:40.000-07:00
diff --git a/Readme.md b/Readme.md
@@ -1,7 +1,7 @@
 
 # classes
 
-  Cross-browser element class manipulation, utilizing the native `.classList` when possible.
+  Cross-browser element class manipulation, utilizing the native `.classList` when possible. This is not designed to be a `.classList` polyfill.
 
 ## Installation
 
