Move Y position, height, and minimized state into TrackView...

... and eliminate some unnecessary calls to SubstitutePendingChangedTrack,
because the track and the substitute store Y and height in their shared
TrackView object.

Also make GetMinimizedHeight() virtual to avoid inclusion of TrackPanel.h in
TrackView.cpp.

src/menus/ViewMenus.cpp

@@ -203,15 +203,17 @@ void DoZoomFitV(AudacityProject &project)
    height -= 28;
    
    // The height of minimized and non-audio tracks cannot be apportioned
+   const auto GetHeight = []( const Track *track )
+      { return TrackView::Get( *track ).GetHeight(); };
    height -=
-      tracks.Any().sum( &Track::GetHeight ) - range.sum( &Track::GetHeight );
+      tracks.Any().sum( GetHeight ) - range.sum( GetHeight );
    
    // Give each resized track the average of the remaining height
    height = height / count;
    height = std::max( (int)TrackInfo::MinimumTrackHeight(), height );
 
    for (auto t : range)
-      t->SetHeight(height);
+      TrackView::Get( *t ).SetHeight(height);
 }
 }