Split logger.h into log_reader and log_writer

Much simpler!

Change-Id: I6c4ee363b56b67dac40c456261bbed79d01b8eb6
diff --git a/y2020/control_loops/drivetrain/localizer_test.cc b/y2020/control_loops/drivetrain/localizer_test.cc
index d440aaf..d195b5d 100644
--- a/y2020/control_loops/drivetrain/localizer_test.cc
+++ b/y2020/control_loops/drivetrain/localizer_test.cc
@@ -3,7 +3,7 @@
 #include "gtest/gtest.h"
 
 #include "aos/controls/control_loop_test.h"
-#include "aos/events/logging/logger.h"
+#include "aos/events/logging/log_writer.h"
 #include "aos/network/message_bridge_server_generated.h"
 #include "aos/network/team_number.h"
 #include "aos/network/testing_time_converter.h"