- Buttons on dialogs were not getting width and height
- Tooltip buttons were getting standard button spacing when they
should be closer to their corresponding menu button
- Several buttons and other elements had containers just to get
spacing in button sets; rename button-container class to
button-set-item and apply directly to elements where possible.
Instead of having the menu keeping track of whether it's open, we now
leave it up to the surrounding component to mount and unmount it. This
avoids bubbling issues when listening for events on an external toggle
button.
We also now use the recommended callback style for refs instead of
named refs.
