python initial setup with 3.x compatibility

 - The first two lines are as same as #! snippet defined at top,
   currently snippets can't be used inside another one so it was
   important.
 - The __future__ imports does the work of compatibility for 2.x scripts
 - import sys is not so important but is casual, frequently used in
   sys.argv and sys.exit
add print function snippet

 - Also availabe on Python 2.x with print_function future import
add open function to open files from disk