Added support for `Environment.compile_expression`.

--HG--
branch : trunk
diff --git a/CHANGES b/CHANGES
index 3b50265..c2d64e9 100644
--- a/CHANGES
+++ b/CHANGES
@@ -41,6 +41,9 @@
 
 - added a joining helper called `joiner`.
 
+- added a `compile_expression` method to the environment that allows compiling
+  of Jinja expressions into callable Python objects.
+
 Version 2.0
 -----------
 (codename jinjavitus, released on July 17th 2008)