The Github creation flow should automatically scroll the browser window so the active step is fully visible.

1. Top edge of the step should be below the top of the window
2. Bottom edge of the step should be above of the window.
3. In cases where the window is smaller than the step, position so the top edge of the step is aligned with the top edge of the window.
4. Extra credit use a nice animation for the scroll.

Notes:

1. Ideally this behavior might be baked into the MultiStepFlow component so that it just "does the right thing" when steps are added or removed.
2. Perhaps the scroll behavior can be further generified, although
3. If the user has scrolled near the bottom of a long flow, then scrolls up and selects a prior step, the total height of the page will change and this could lead to odd scrolling behavior. Will need extra testing.