python 2/3 compatible syntaxe in image_encoding_speed_test (fix #52)

Author: yohanboniface

test/python_tests/image_encoding_speed_test.py

@@ -113,7 +113,7 @@ def aerial_24():
             t = Timer(aerial_24)
             run(aerial_24, aerial_24_im, c, t)
 
-    for key, value in sorted(sortable.iteritems(), key=lambda k, v: (v, k)):
+    for key, value in sorted(sortable.items(), key=lambda i: (i[1], i[0])):
         s = results[key]
         min_ = str(s[0])[:6]
         avg = str(s[1])[:6]