Exit upon receiving an Exception

Assets/Editor/BuildTiltBrush.cs

@@ -883,7 +883,10 @@ static void CommandLine()
             {
                 string oneLineMessage = Ex.Message.Replace("\n", " ");
                 Debug.LogErrorFormat("::error ::Build failed with Exception <<{0}>>", oneLineMessage);
-                throw;
+                Debug.LogError($"{Ex.StackTrace}\n\n");
+                // For some reason, Unity exits if we rethrow this (or never caught it), but with an exit code of 0. So instead, we'll explicitly exit here
+                // throw;
+                Die(6, oneLineMessage);
             }
         }
     }