It was written to support a Goldcut ABH 721 [Refine MH721, Jinka JK721]
Speed and pressure of the devices cannot be software-controlled. This is done on the device.

These devices are simple HPGL plotters, thus the driver should support many more devices.
Maybe helpful with t-oster/VisiCut#256

Changed Structure: DitheringAlgorithm, LaserCutter and LaserProperty implement the Customizable Interface. Thus Dithering-Algorithms can have Options (and are clonable)

- Deleted useless UnitTests (were interactive anyway)
- LAOS driver uses now floats instead of ints (untested)