Can't clone pyobjus on Windows, MS-DOS reserved word as a folder

>git clone https://github.com/kivy/pyobjus
```sh
Cloning into 'pyobjus'...
remote: Enumerating objects: 219, done.
remote: Counting objects: 100% (219/219), done.
remote: Compressing objects: 100% (146/146), done.
emote: Total 1944 (delta 146), reused 131 (Receiving objects: 98% (190delta 72), pack-reused 1725
Receiving objects: 100% (1944/1944), 763.17 KiB | 0 bytes/s, done.
Resolving deltas: 100% (1221/1221), done.
Checking connectivity... done.
fatal: cannot create directory at 'objc_classes/aux': Invalid argument
warning: Clone succeeded, but checkout failed.
You can inspect what was checked out with 'git status'
and retry the checkout with 'git checkout -f HEAD'
```

This is happening due to `aux` being a reserved MS-DOS word and [the only workaround](https://superuser.com/a/129146/571014) is *very* annoying. In case we want people to contribute to PyOBJus from Windows (e.g. docs if not the code) we'll need to rename it. That folder is most likely used on one of the iOS things hopefully only under Plyer, but I guess that something would also be available under Kivy-iOS, so it'll break things and I don't have any iOS device to test it with.

Start by searching the repository for objc_classes/aux and every reference to that directory, then inspect the related iOS or Plyer usage mentioned in the issue. Test a fresh checkout on Windows or another environment affected by MS-DOS reserved names; done means the repository checks out without the reserved folder failure and all references use the renamed path.

Written by the indexing model from the issue text.