Need to explicitly set RGB pixel_order

[caternuson]

This PR:
adafruit/Adafruit_CircuitPython_seesaw#102
Fixed it so bpp and pixel_order are now internally consistent. But the default set by the seesaw library is RGBW (unsure why). This previously worked since it relied on the essentially RGB behavior when bpp and pixel_order were the inconsistent defaults. But now it does not work, due to the RGBW default. See comment here:
adafruit/Adafruit_CircuitPython_seesaw#101 (comment)

[caternuson]

Closing. Should be fixed with #19.