Set python3 shebang

Author: bahill

src/ExampleModule.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 from ExampleModule_functions import *
 import argparse
 import humanfriendly

src/ExampleModule_command_line_call.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 import os
 import sys
 from subprocess import call

src/ExampleModule_functions.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 # Here is where I'd put my functions, if I had any!
 def empty_function():
     return