Proposal: merge zartnet into zdmx

[fieldOfView]

zartnet and zdmx have the same functionality, the only difference is the output hardware. I propose we make one killer dmx app, with a command-line option to use either dmx-over-usbserial, or dmx-over-ethernet (artnet).

[sphaero]

Marketing technical it might be preferred to have zartnet and zdmx explicitly... however from a technical perspective your approach is preferred...