Popup visual changes

- Don't remove elevation during animation (b/62905720)
- Other adjustments (b/35766387)
  - Add "gutter" between notification and shortcuts
  - Change shortcuts to always be primary color (e.g. white)
  - Scale down shortcut icons when notifications present
  - Apply icon extracted color to "Notifications" header

Change-Id: Idf791dc76d15d05d246000ad73810916d7cd1750