Use elementtree from python 2.5 if available

--- a/pudding/ext/svgelements.py~	2006-07-02 10:40:41.000000000 +0200
+++ b/pudding/ext/svgelements.py	2008-09-27 16:02:03.000000000 +0200
@@ -22,7 +22,10 @@
 try:
 	from elementtree import ElementTree
 except ImportError:
-	raise "You need elementtree from http://effbot.org/zone/element-index.htm"
+	try:
+		from xml.etree import ElementTree
+	except ImportError:
+		raise "You need elementtree from http://effbot.org/zone/element-index.htm"
 
 try:
 	import cairo
