Convert gyro_reading over to event loops.

LPD8806 wasn't going to fit in well, but it's never been used on a
robot.  So take the easy way out and remove it.

Change-Id: Ib4d29b40d63a8663878ff1b074057be8b2df9259
diff --git a/frc971/control_loops/drivetrain/drivetrain.h b/frc971/control_loops/drivetrain/drivetrain.h
index 39d7054..33ff770 100644
--- a/frc971/control_loops/drivetrain/drivetrain.h
+++ b/frc971/control_loops/drivetrain/drivetrain.h
@@ -15,6 +15,7 @@
 #include "frc971/control_loops/drivetrain/polydrivetrain.h"
 #include "frc971/control_loops/drivetrain/splinedrivetrain.h"
 #include "frc971/control_loops/drivetrain/ssdrivetrain.h"
+#include "frc971/queues/gyro.q.h"
 #include "frc971/wpilib/imu.q.h"
 
 namespace frc971 {
@@ -49,6 +50,7 @@
 
   ::aos::Fetcher<LocalizerControl> localizer_control_fetcher_;
   ::aos::Fetcher<::frc971::IMUValues> imu_values_fetcher_;
+  ::aos::Fetcher<::frc971::sensors::GyroReading> gyro_reading_fetcher_;
   LocalizerInterface *localizer_;
 
   StateFeedbackLoop<7, 2, 4> kf_;