Black box: the queries of the user's train worked out once a read, lights as the driver checks them

- The stations, the signals passed, the horn points, the couplings, the
  consists and the timetable progress of the user's train are kept until
  a read adds something; the views asked for them every frame, which on
  a long session with many trains took the window down. A read that adds
  nothing no longer counts as a change.
- The lights are checked against the lamps the vehicles at the ends have
  (written by the simulator from now on), as its driver checks them: Pc 1
  without the upper headlight, with the auxiliary lamps, Pc 5 with the
  rear-end signals. Only while the user drives: the autopilot's lights
  are its own.
- A train off the platform counts at both ends: its head past the stop
  point as well as its tail before the platform's end.
- A recording without the couplings keeps the timetable for any vehicle
  of the user.
- A signal passed at danger is ringed on the map only once it was.
- In the tapes window a black box opens on a click or Enter, not when
  the arrow keys go over it.
- The viewer's screenshot of a window not laid out saves nothing and
  still closes.

StarterNG.Tests/BlackBox/PlatformTests.cs

@@ -31,6 +31,22 @@ public class PlatformTests
         Assert.Equal(201, stop.PlatformLength);
     }
 
+    [Fact]
+    public void A_train_whose_head_stands_past_the_stop_point_is_off_the_platform_by_that_much()
+    {
+        var stop = Stop(-5f, 129.8f, 201);
+        Assert.False(stop.OnPlatform);
+        Assert.Equal(5, stop.OffPlatform, 1);
+    }
+
+    [Fact]
+    public void A_metre_off_still_counts_as_along_the_platform()
+    {
+        var stop = Stop(-1f, 129.8f, 201);
+        Assert.True(stop.OnPlatform);
+        Assert.Equal(1, stop.OffPlatform, 1);
+    }
+
     [Fact]
     public void A_train_within_the_platform_is_along_it()
     {