Marblevator remix

Small modifications and addons to the execelent design by gzumwalt and Linax.

I kept having problems that the edges of the track would rip off during printing, so I added a small block of support to the tracks, 1cm long, as wide as the track.
This is only 0.2mm thick, so should only be on 1-2layers and can be cut off after printing.

Modified the arm to be 0.2mm less wide, since on my printer at least the original one is a bit too thick, since the top already keeps it fixed somewhat, the