Add back a CSSMinFilter filter for compatibility.

compressor/filters/cssmin/__init__.py

@@ -3,8 +3,8 @@ from compressor.filters import CallbackOutputFilter
 
 class CSSCompressorFilter(CallbackOutputFilter):
     """
-    A filter that utilizes Yury Selivanov's Python port of
-    the YUI CSS compression algorithm: https://pypi.python.org/pypi/csscompressor
+    A filter that utilizes Yury Selivanov's Python port of the YUI CSS
+    compression algorithm: https://pypi.python.org/pypi/csscompressor
     """
     callback = "csscompressor.compress"
     dependencies = ["csscompressor"]
@@ -16,3 +16,6 @@ class rCSSMinFilter(CallbackOutputFilter):
     kwargs = {
         "keep_bang_comments": True
     }
+
+# This is for backwards compatibility.
+CSSMinFilter = rCSSMinFilter