Version 3.1.1

• Fix: MenuItem.getSubMenu now returns a support instance rather than a
  native instance.
• Fix: Fragment methods onAttach and onInflate incorrectly regressed to use
  Activity instead of a FragmentActivity in their method signatures.
• Fix: Retained fragments not being re-attached on pre-3.0 when attached to
  android.R.id.content upon activity recreation.
• Fix: onPrepareOptionsMenu not dispatched to fragments. This still will only
  occur if the activity method returns true (which is the default).
• Fix: Menu.findItem not returning null when the item was not found on
  Android 3.0+.