Tune rejection score to work on the side of the cargo ship

James did some simulations and this makes it significantly better.

Change-Id: I79499c1d4d848fa7b90540f3df725e6a03e932d0
diff --git a/y2019/control_loops/drivetrain/localizer.h b/y2019/control_loops/drivetrain/localizer.h
index 58b6901..1571fec 100644
--- a/y2019/control_loops/drivetrain/localizer.h
+++ b/y2019/control_loops/drivetrain/localizer.h
@@ -100,7 +100,7 @@
   // The threshold to use for completely rejecting potentially bad target
   // matches.
   // TODO(james): Tune
-  static constexpr Scalar kRejectionScore = 1000000.0;
+  static constexpr Scalar kRejectionScore = 1.0;
 
   // Checks that the targets coming in make some sense--mostly to prevent NaNs
   // or the such from propagating.