Allow the supplied toolbar config to create new items as well as new groups. Previously I hadn't thought that this would be that useful as it would have been hard to add functionality to the new item. However now it's a lot easier to provide custom functionality so allowing new toolbar items makes a lot more sense.
Add an example of a new toolbar item that invokes a supplied function.
Move the new style menus from the main toolbar definition into the styles example.
The styles2.html example is currently broken after the style menus were removed from the base toolbar definition. I don't want to make it work again by replicating large chunks of the styles.html example, so until I think of a better solution mark it as broken and move on.