3.4.6 Stable Release of Grbl Controller

I added some minor fixes and improved stability in 3.4.6. Additionally, I built a PC and Mac version. From my experience with it, I would recommend using 3.4.6 at this time for PC, Mac, Linux and Raspberry Pi.

Note – if you have many (hundreds of) lines of gcode, the Raspberry Pi version can bog down when it refreshes the status window (this was due to a fix I put it to show horizontal scroll bars). I am looking at fixing this by either limiting the maximum number or removing the horizontal scroll bars when building for Linux.