Dual blade selector for MMU2 (experimental)

Update: 5 Jun 19. I had a problem with occasional jams during loading with blunt tips hitting the blade. I've modified the selector and blade cover a bit further to prevent this from happening. I've also made the blade "sockets" much deeper and added press-plates to the blade cover to make the blades more secure. Print the selector in its usual orientation (front down), and the blade cover on its back.

I made this to attempt to solve the problem where filament isn't quite retracted all the way to the idler body, and is dragged by the selector.

This modified selector has a much greater cutting effectiveness. The PTFE tube holding plate has higher blade grooves so that filament can't be lifted out and dragged as the blade passes across. There are two blades, so cutting can occur in both directions.

Also includes a slightly refined entry port. Not as tapered as my other selector, but still with a bit of leeway for non-straight filament.

Still being tested - so consider this experimental.

Also includes text if you want to add MMU text.