Added detection of bad index zeroing pulse.

Change-Id: I1607ce0d37b336136a4a278afc8a0f2897d1c597
diff --git a/frc971/zeroing/zeroing.h b/frc971/zeroing/zeroing.h
index 7fa2262..08911ac 100644
--- a/frc971/zeroing/zeroing.h
+++ b/frc971/zeroing/zeroing.h
@@ -102,6 +102,12 @@
   // Marker to track whether an error has occurred. This gets reset to false
   // whenever Reset() is called.
   bool error_;
+  // Stores the position "start_pos" variable the first time the program
+  // is zeroed.
+  double first_start_pos_;
+  // Value between 0 and 1 which determines a fraction of the index_diff
+  // you want to use.
+  double allowable_encoder_error_;
 };
 
 // Populates an EstimatorState struct with information from the zeroing