It is now possible to configure each individual command that will be compiled in the shell:
```
shell = { commands = {'ls', 'ver', 'type' } }
```
If not specified, all the available commands will be compiled (which is backwards compatible).
Also, the `advanced_shell` attribute is gone, replaced with an `advanced` key in the shell
configuration. So write this:
```
shell = { advanced = true }
```
instead of this:
```
advanced_shell = true
```