Specifying nautilus version

Created by: SunyataZero

We may want to specify the nautilus version when importing nautilus. The warning seems harmless in itself but could point to a problem that may occur when running another version of Nautilus

sys:1: PyGIWarning: Nautilus was imported without specifying a version first. Use gi.require_version('Nautilus', '3.0') before import to ensure that the right version gets loaded.