Split logger.h into log_reader and log_writer

Much simpler!

Change-Id: I6c4ee363b56b67dac40c456261bbed79d01b8eb6
diff --git a/y2019/control_loops/drivetrain/drivetrain_replay.cc b/y2019/control_loops/drivetrain/drivetrain_replay.cc
index 69cce4f..97b4c2b 100644
--- a/y2019/control_loops/drivetrain/drivetrain_replay.cc
+++ b/y2019/control_loops/drivetrain/drivetrain_replay.cc
@@ -1,7 +1,8 @@
 #include <iostream>
 
 #include "aos/configuration.h"
-#include "aos/events/logging/logger.h"
+#include "aos/events/logging/log_writer.h"
+#include "aos/events/logging/log_reader.h"
 #include "aos/events/simulated_event_loop.h"
 #include "aos/init.h"
 #include "aos/json_to_flatbuffer.h"