Add encoding comment to source files

This is a minor thing.  It’s a convention, not a rule (obviously)—but it’s also a best practice.

Many text editors look for this kind of comment as the first line—or second line, if there is a shebang (the `#!/usr/bin/env python`, or whatever else)—and make use of this to determine the file’s encoding.

github/InputFileContent.py

@@ -1,3 +1,5 @@
+# -*- coding: utf-8 -*-
+
 # Copyright 2012 Vincent Jacques
 # vincent@vincent-jacques.net