Add ids to flatbuffer fields in y2012, y2016, frc971, and aos

Change-Id: I9ed9006ce6224e2df0459df47771786b928164a1
diff --git a/frc971/wpilib/imu_batch.fbs b/frc971/wpilib/imu_batch.fbs
index 8029ced..1483314 100644
--- a/frc971/wpilib/imu_batch.fbs
+++ b/frc971/wpilib/imu_batch.fbs
@@ -3,7 +3,7 @@
 namespace frc971;
 
 table IMUValuesBatch {
-  readings:[IMUValues];
+  readings:[IMUValues] (id: 0);
 }
 
 root_type IMUValuesBatch;