test: Move from static gobject bindings to GI

Use GLib gobject-introspection bindings so that we can also use the scripts
with Python 3.
test: Fix inconsistent tab/space usage

This is disallowed in Python 3.
test rilmodem: Ensure property keys is a list

In Python 3 it is an iterator, so always convert it to a list. This change is
compatible with Python 2.
test: Convert to Python 3

Change raw_input() to input() and unicode to str. This is *not* compatible with
Python 2.
test: Switch scripts to run with Python 3

Update the hashbangs.