Checkerboard xyz orientation

[Morgan Turner]

Checkerboard axes are currently y+ down the column, x+ across rows, and z+ orthogonal down. Would like option for z+ up.

[Benjamin Knorlein]

fixes #173 : Added an option in the Settings which allows to invert an axis of the checkerboard to make the z-axis look up

→ <<cset 441c7379a019>>