Improved bbcache and documented it.

--HG--
branch : trunk
diff --git a/CHANGES b/CHANGES
index af3ef4c..775b709 100644
--- a/CHANGES
+++ b/CHANGES
@@ -30,6 +30,8 @@
 
 - fixed a bug with empty statements in macros.
 
+- implemented a bytecode cache system.  (:ref:`bytecode-cache`)
+
 Version 2.0
 -----------
 (codename jinjavitus, released on July 17th 2008)