Make buttons more tab friendly.  Focus progressive button.

- Convert close button to <a> tag and handle the same as other buttons
  Which puts it in the same tab order as the other buttons.
- Progressive button is focused when step shows
- tabbing from progressive button goes down the dom order
- shift tabbing from the progressive goes to the x button

Bug 66545
Change-Id: I1446c66544589262cb7dedb050452a8c138376d7