convert shebang lines: python -> python3
diff --git a/Demo/scripts/markov.py b/Demo/scripts/markov.py
index 990c972..7c08bdb 100755
--- a/Demo/scripts/markov.py
+++ b/Demo/scripts/markov.py
@@ -1,4 +1,4 @@
-#! /usr/bin/env python
+#! /usr/bin/env python3
 
 class Markov:
     def __init__(self, histsize, choice):