DO NOT MERGE. Integrate fragment work from master

Back-port new fragment detach APIs from support lib.

This allow a much cleaner implementation of things like the
fragment pager class.

Integrate from support lib: fix restore of list state.

The FragmentManager/ListFragment impl was restoring the list
state before setting its adapter.  This caused the list view to
lose the state, since it gets cleared as part of setting the
adapter.  Now the fragment manager waits on restoring the view
hierarchy state until after it has done onActivityCreated(),
at which point we have set the adapter.

It would be nice to make list view less fragile in this regard,
but that is for a different change.

Change-Id: I38606ef7d0b06478995f3fb7726aead67420e172