Refactor for non-lab version

Two versions of PaletteFader are contained in the cedargrove_palettefader package folder, palettefader and palettefader_ulab. The faster of the two is palettefader_ulab, requiring CircuitPython with ulab as a built-in module. Certain CircuitPython distributions and versions may not support ulab; check your specific implementation. For example, ulab is not included in MatrixPortal distributions after CircuitPython version 7.3.2.