Baseline cube without texture doesn't have all faces rendered

[przet]

Rotation logic changed for all 3 cubes to allow for visual inspection of all faces

[przet]

Some things I am going to leave to other issues (as I want to go over to windows first):

1. Can fix the rotation logic to inspect the top/bottom faces without needing to go around a full circle (as we then cover faces we already have seen).
2. At least on the middle cube, there is a model matrix reset issue (evident in the snapping to a different face).
3. If I am working on 1 and 2, it would be good to also reorder the slots in a more logical fashion (the third slot is the middle cube)