Update ApiDemos to show active password status

* Add Check Password button
* Use it to report overall password status - isActivePasswordSufficient()
  and various password settings.
* Fixed a minor bug that cause the password quality to be reset to
  "unspecified" every time you start the activity.
* Leave the two password buttons enabled all the time (set password
  can be used when not active, and check password just puts up a toast
  explaining why it can't be used when inactive.)

This code can be used to confirm bug b/4445007 and hopefully its fix, too.

Change-Id: I136706072257d2e49184a29b0aa5d7a524960c40
3 files changed