Separate out CPU-heavy portion of IMU zeroing

This lets us run the hard stuff only once per drivetrain iteration,
rather than 10 times per drivetrain iteration.

Change-Id: I262f41cafaf3b34fbd7f5205896dfdcde808db77
diff --git a/frc971/zeroing/imu_zeroer.h b/frc971/zeroing/imu_zeroer.h
index b55c6dd..fd82571 100644
--- a/frc971/zeroing/imu_zeroer.h
+++ b/frc971/zeroing/imu_zeroer.h
@@ -22,7 +22,10 @@
   ImuZeroer();
   bool Zeroed() const;
   bool Faulted() const;
-  void ProcessMeasurement(const IMUValues &values);
+  void InsertMeasurement(const IMUValues &values);
+  // PErforms the heavier-duty processing for managing zeroing.
+  void ProcessMeasurements();
+  void InsertAndProcessMeasurement(const IMUValues &values);
   Eigen::Vector3d GyroOffset() const;
   Eigen::Vector3d ZeroedGyro() const;
   Eigen::Vector3d ZeroedAccel() const;