Upgrade Bluetooth pairing dialogs for ICS.

* Change Bluetooth pairing dialogs to match ICS wireframes.
* Default to numeric soft keyboard for PIN entry, and add checkbox
  to allow user to switch to alphanumeric keyboard if necessary.
* Move all Bluetooth advanced settings into action bar menu.
* Toggle visibility by touching "My device" entry in devices list.

Change-Id: Ic2377eb4364f41d215181cb1e3933997c9db9106