Add option to select track that exceeds renderer capabilities

Leaving disabled by default for now, but we may want to consider
enabling it by default. Note that in V1 for ExtractorSampleSource
the behaviour was equivalent to this option being enabled, since
we didn't perform capabilities checks. For DASH/SS/HLS the V1
behaviour was equivalent to this option being disabled.

The type in PlayerActivity has been changed just to make it
easier to add a line that calls setParameters.

Issue: #2034
Issue: #2007
Issue: #2078

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=140477568

demo/src/main/java/com/google/android/exoplayer2/demo/PlayerActivity.java

@@ -55,7 +55,6 @@
 import com.google.android.exoplayer2.source.smoothstreaming.SsMediaSource;
 import com.google.android.exoplayer2.trackselection.AdaptiveVideoTrackSelection;
 import com.google.android.exoplayer2.trackselection.DefaultTrackSelector;
-import com.google.android.exoplayer2.trackselection.MappingTrackSelector;
 import com.google.android.exoplayer2.trackselection.MappingTrackSelector.MappedTrackInfo;
 import com.google.android.exoplayer2.trackselection.TrackSelection;
 import com.google.android.exoplayer2.trackselection.TrackSelectionArray;
@@ -109,7 +108,7 @@ public class PlayerActivity extends Activity implements OnClickListener, ExoPlay
 
   private DataSource.Factory mediaDataSourceFactory;
   private SimpleExoPlayer player;
-  private MappingTrackSelector trackSelector;
+  private DefaultTrackSelector trackSelector;
   private TrackSelectionHelper trackSelectionHelper;
   private DebugTextViewHelper debugViewHelper;
   private boolean playerNeedsSource;