Story 425 Nearby: Cache last known location/nearby places

Add an additional level of caching to this page so that back button
is a little more responsive. Note nearby.js runs at bottom of page so
there is still a slight delay. Lets not make mobile.stable load at top
of page just for this..

Change-Id: I458e3ca60c56e25bda65eb4675390b13f4acd91d
Merge "Story 425 Nearby: Cache last known location/nearby places"