Small changes to XZ gantries and electronics holders

Hey everyone, we have made some small updates to the XZ gantries and electronics holders to make the Mill One slightly better. These improvements have been made to improve ease of manufacturing.

XZ gantries:

We have changed the spacing slightly on the gantry to allow for more freedom of adjustment for the v wheels. Some users may have noticed that there is not a lot of room to tighten down on the v wheels. We have had two different batches of aluminum having come from two different sources. Thus some users have angle aluminum that is slightly wider than the first batch which reduces the amount of space to adjust the v wheels.

If you received a Mill One in the past two weeks, you will have received the latest version of the XZ gantry.

Electronics enclosure:

We have made a small change to the size of the plastic around the notch that holds the cover on the electronics enclosure to make it much more difficult to break. You can find the latest model here: https://www.thingiverse.com/thing:2288412