Add python shebang snippet

vim/UltiSnips/python.snippets

@@ -5,3 +5,7 @@ snippet future "Import from future" !b
 from __future__ import (division, absolute_import, print_function,
                         unicode_literals)
 endsnippet
+snippet #! "Python shebang" !
+#!/usr/bin/env python2
+# encoding: utf-8
+endsnippet