Mixmaster cab upgrade split for color

Took the excellent mixmaster upgrade by artyve and split into separate windows, grill, and bumper parts for color printing. Also made some small changes to the sliding rails so it can slide down further on his back in bot mode without removing it and the connector to cover the holes on top (have not tested those changed parts yet).

Now I just need to find constructicon green filament...heard a rumor that lulzbot green is a dead match