The lines drawn, may not be correct #13

I just noticed a minor bug which draws the wrong line as the program runs.

line 200:
xLine, yLine = linePixels(coords[bestPin], coord)

I think should look like that:
xLine, yLine = linePixels(oldCoord, coords[bestPin])

Great project though, and a good excuse to finally dive a little more into numpy. Thank you for sharing.