duplicate gamma correction fix
duplicate gamma correction fix

usefulthink/node-rpi-ws281x-native,usefulthink/node-rpi-ws281x-native,usefulthink/node-rpi-ws281x-native,raspberry-node/node-rpi-ws281x-native,raspberry-node/node-rpi-ws281x-native,beyondscreen/node-rpi-ws281x-native,raspberry-node/node-rpi-ws281x-native,beyondscreen/node-rpi-ws281x-native,beyondscreen/node-rpi-ws281x-native