Nimble V1 mounts for the Railcore system

#### Mounts for the Railcore system.

Here are a few mounts to use a Nimble on the Railcore system. Currently, there is a mount for the V6 and one for the Mosquito hot end.

If you need a different hot end mount, let me know.

Some holes look like blind holes, but that is done to make sure the holes stay a nice shape while printing. Otherwise, there would be overhangs that are more difficult to print.

The STL models are checked and optimised. The parts that need a different orientati