Split logger.h into log_reader and log_writer

Much simpler!

Change-Id: I6c4ee363b56b67dac40c456261bbed79d01b8eb6
diff --git a/y2020/control_loops/superstructure/BUILD b/y2020/control_loops/superstructure/BUILD
index d659920..3ea3dbf 100644
--- a/y2020/control_loops/superstructure/BUILD
+++ b/y2020/control_loops/superstructure/BUILD
@@ -105,7 +105,7 @@
         ":superstructure_status_fbs",
         "//aos:math",
         "//aos/controls:control_loop_test",
-        "//aos/events/logging:logger",
+        "//aos/events/logging:log_writer",
         "//aos/testing:googletest",
         "//aos/time",
         "//frc971/control_loops:capped_test_plant",