Update to latest The Things Uno SDK

[johanstokking]

This is an old fork of The Things Uno SDK. The current version, in TheThingsNetwork/sdk/devices/TheThingsUno is 0.15+ afaik, with downlink support.

[FokkeZB]

My mistake... used my local, out-dated version. I've updated it and renamed all use of TheThingsUno and ttu to TheThingsNetwork and ttn

[FokkeZB]

Aaaaand fixed the fix 😬

[johanstokking]

Thanks