Add dividers between buttons at the top

[rerpha]

As a user I would like it to be clearer that at any point I can click on one of the buttons at the top and it'll take me to the screen I want. Yesterday I confused myself by hitting "Get base tune" and thought I couldn't go back to seeing what was in progress because it wasn't immediately clear that the buttons at the top were actually buttons.

I am happy to make this change and submit a PR, just logging it here.