This will probably solve the last common setup issue. Starting Wine can
take a second so this check is only repeated when either Wine or
yabridge get updated.
Xonsh 0.9.14's which implementation is broken so I left it out:
```shell
$ env -i HOME=$HOME xonsh -l -c 'which <anything>'
xonsh: For full traceback set: $XONSH_SHOW_TRACEBACK = True
KeyError: 'PATH'
```
When creating copies with yabridgectl. This should at least give an
advance warning that some additional steps are required when first
setting up yabridge.