Add support for Raspberry Pi 3
Add support for Raspberry Pi 3

Closes #44

codedust/gluon-firmware-wizard,codedust/gluon-firmware-wizard,codedust/gluon-firmware-wizard,freifunk-darmstadt/gluon-firmware-wizard,freifunk-darmstadt/gluon-firmware-wizard,freifunk-darmstadt/gluon-firmware-wizard