v6 migration

#541 # Question

Hi, great job on the v6. It looks like a very nice upgrade.
Yet, when I tried to migrate one of my presentation I found some key features were missing:

- With the progress now in the template, it's hard to be able to change its color per slide
- The fun pacman-style progress is now a simple dot
- The "fit" attribute was really a nice addition, from what I see it's not anymore part of the API

Do you have in your plans to add them or should we stay on the old version?

Also, same as the old version, it's still not possible to split slides per file with a "normal" component usage.

This is not working:
```
import Page1 from './slides/page1'

...

```

We have to still use this "way" of including the slide:
```

{/* Sad hack to be able to split slides per files */}
{Landing()}
```

It is a wanted behavior, if not, what I am missing?

Regards.