napari-imagegrains demo

To get started without having to first setup a dataset, find the correct widget etc. we provide a demo widget that will allow to download a demo dataset, models and open the first processing widget for you. For that, head to `Plugins -> ImageGrains -> ImageGrain Demo Widget. You should see the following window appear:

Now click on Download demo data and you should see the following:

For the next steps, head to the documentation for the ImageGrain Processing Widget.