Implement issue #3094621 and #3094609 - wipe sd card

3094621: add "wipe sd card" option to factory data reset
3094609: collapse unmount/format into one command

Implements requested UI changes.  Also some final tweaks to
Manage Applications.

Change-Id: I0219195dd0c74d8c003ef1c3f6e09714859d7f89