Group by content-type in generated menu

Issue Summary

When generating a menu by checking some content types under "Generate menu links for assigned content" you get links to each of the nodes of that type. I'd like an extra checkbox "Generate menu links for each content type.".

An example. If you have the container Color with the categories Red, Green and Blue and then the content types Car and Fruit which can be assigned to these categories I would like the menu to show:

Creating content types is also a kind of categorisation and I would like this categorisation to integrate with the menu built by the category module.