Add better support for dynamically sized TabViews

[Freddo3000]

Add better support for dynamically sized TabViews

[geom3trik]

I'm not sure I understand what you mean by your first point. What do you mean by data contained within a tab? Typically your data should be in a model, probably further up the tree than the tabview.

Yes it's true that on_select and with_selected moves the managements of the tab index to your own data, but this is intentional as it gives you full control of the selected tab without needing messy events to sync with the internal tabview index.

If you could provide an example scenario of what you're trying to achieve I think that would help me understand what features you need me to add.