rM2svg needs update for other pens

[zeigerpuppy]

The rM2svg works well for conversion to SVG (and renders as individual strokes which is better than the reMarkable native SVG export).

I noticed that it could use support for more pen types.

For instance, I hacked up support for mechanical pencil ( # 17) using the existing pen # 7:

(line 171 -3):

            elif pen == 7 or pen == 17: # Pencil-Sharp
                width = 16 * width - 27
                opacity = 0.9

Not sure of all the pen mappings but would be good to update the script...

https://github.com/reHackable/maxio/blob/master/tools/rM2svg