Android: Story Nav Overlay

Basic implementation of the overlaid story navigation buttons.  This currently just navigates forward and back thru the list (read: left/right corresponding to the button pressed) in the same fashion dictated by the configured story ordering.  The functionality to search for unreads will take some time yet, since the underlying libraries are missing some pretty big moving parts to support it.

Also includes one random crash fix I forgot to pull before starting.

Let me know any feedback on look and feel or functionality.  Tried to get it as close as possible to iOS based on the video you sent.  I'm working on upgrading the underlying data provider so that we can take a crack at the next-unread functionality.