Included sample activities/fragments to showcase how to
use GuidedStepFragment in half screen mode.
Change-Id: I9eefe417ddf79b0dfe896a5cec25b7c7cd3a41e7
Include all leanback support version of fragment except
PlaybackOverlayFragment missing a support version of PlaybackControlHelper.
Change-Id: Icb5c99e8677630e8541b22b009051dd3908d4f35