py3k: Import reduce function

reduce() is no longer a built-in function in py3k.

PIL/ImageFilter.py

@@ -15,6 +15,8 @@
 # See the README file for information on usage and redistribution.
 #
 
+from functools import reduce
+
 class Filter:
     pass
 

PIL/ImageOps.py

@@ -19,6 +19,7 @@
 
 import Image
 import operator
+from functools import reduce
 
 ##
 # (New in 1.1.3) The <b>ImageOps</b> module contains a number of

PIL/ImageStat.py

@@ -23,6 +23,7 @@
 
 import Image
 import operator, math
+from functools import reduce
 
 ##
 # The <b>ImageStat</b> module calculates global statistics for an