Make the main activity a guided step that allows the selection of
other activities. Add a dedicated activity to represent a
sequence of GuidedStepFragments.
b/18935698
Change-Id: I16142f4d7e87b3f2f02b812faa9bff82ecf5361c
SupportLeanbackDemos starts out with a fully functional app with a
BrowseFragment. Still need to add examples with cursors, hovercards,
and more.
Change-Id: I845d5b92c29a5585af7968b08e7daa11b2996f5a
