Zoom debug viewer in

Images are small, so let's do 2 pixels per pixel.

Change-Id: I77e28c236fbef9b67ae29793227208caea088dc3
diff --git a/y2019/vision/debug_viewer.cc b/y2019/vision/debug_viewer.cc
index 1db8e33..35f2af3 100644
--- a/y2019/vision/debug_viewer.cc
+++ b/y2019/vision/debug_viewer.cc
@@ -59,7 +59,7 @@
 
   void InstallViewer(aos::vision::BlobStreamViewer *viewer) override {
     viewer_ = viewer;
-    viewer_->SetScale(0.75);
+    viewer_->SetScale(2.0);
     overlays_.push_back(&overlay_);
     overlays_.push_back(finder_.GetOverlay());
     viewer_->view()->SetOverlays(&overlays_);