Create zeroing estimator for absolute and absolute encoder

The same as pot and absolute encoder, but with an absolute encoder that
doesn't do index pulses, but can only go through one rotation.

Change-Id: I4b41df7e93ac4454c9aec0fee3c072b4bc9a57c1
diff --git a/frc971/control_loops/control_loops.fbs b/frc971/control_loops/control_loops.fbs
index 4377541..f510085 100644
--- a/frc971/control_loops/control_loops.fbs
+++ b/frc971/control_loops/control_loops.fbs
@@ -130,6 +130,23 @@
   absolute_position:double;
 }
 
+// The internal state of a zeroing estimator.
+table AbsoluteAndAbsoluteEncoderEstimatorState {
+  // If true, there has been a fatal error for the estimator.
+  error:bool (id: 0);
+  // If the joint has seen an index pulse and is zeroed.
+  zeroed:bool (id: 1);
+  // The estimated position of the joint.
+  position:double (id: 2);
+
+  // The estimated absolute position of the encoder.  This is filtered, so it
+  // can be easily used when zeroing.
+  absolute_position:double (id: 3);
+
+  // Estimated absolute position of the single turn absolute encoder.
+  single_turn_absolute_position:double (id: 4);
+}
+
 table RelativeEncoderEstimatorState {
   // If true, there has been a fatal error for the estimator.
   error:bool;