Highlite with Arrow keys#377

Hello,

It would be great to go with the arrow keys left and right to your next or previous fixture, when you highlighted it. I often have the problem, that I look at the stage to highlight my lamp, but miss to touch the little arrow keys on the touchscreen, because I’m not looking in my screen. I hope that is easy to implement in 2.2.0

2.2 uses the arrow keys for Cell / Pool Item selection, and I also think it would be unexpected if the USB Keyboards Arrow buttons would alter fixture selection.