Replace backticks with repr() or "%r"

From SF patch #852334.
diff --git a/Mac/IDE scripts/Widget demos/WidgetTest.py b/Mac/IDE scripts/Widget demos/WidgetTest.py
index f88b059..424e70d 100644
--- a/Mac/IDE scripts/Widget demos/WidgetTest.py
+++ b/Mac/IDE scripts/Widget demos/WidgetTest.py
@@ -79,7 +79,7 @@
 if 0:
 	import time
 	for i in range(20):
-		window.et2.set(`i`)
+		window.et2.set(repr(i))
 		#window.et2.SetPort()
 		#window.et2.draw()
 		time.sleep(0.1)