add support for offsetting potentiometer values to zero

Change-Id: Ic526dd27c4608814e12e7bd0fd33801b69779ca3
diff --git a/frc971/constants.cc b/frc971/constants.cc
index b0cbc6b..b64f52b 100644
--- a/frc971/constants.cc
+++ b/frc971/constants.cc
@@ -116,6 +116,7 @@
             // Zeroing constants for wrist.
             // TODO(sensors): Get actual offsets for these.
             {kZeroingSampleSize, kClawEncoderIndexDifference, 0.0},
+            0.0,
           },
 
           {
@@ -139,6 +140,7 @@
             // Arm zeroing constants: left, right.
             {kZeroingSampleSize, kArmEncoderIndexDifference, 0.0},
             {kZeroingSampleSize, kArmEncoderIndexDifference, 0.0},
+            0.0, 0.0, 0.0, 0.0,
           },
           // End "sensor" values.
 
@@ -180,7 +182,7 @@
             // Zeroing constants for wrist.
             // TODO(sensors): Get actual offsets for these.
             {kZeroingSampleSize, kClawEncoderIndexDifference, 0.0},
-
+            0.0,
           },
 
           {
@@ -203,6 +205,7 @@
             // Arm zeroing constants: left, right.
             {kZeroingSampleSize, kArmEncoderIndexDifference, 0.0},
             {kZeroingSampleSize, kArmEncoderIndexDifference, 0.0},
+            0.0, 0.0, 0.0, 0.0,
           },
           // End "sensor" values.
 
@@ -244,6 +247,7 @@
             // Zeroing constants for wrist.
             // TODO(sensors): Get actual offsets for these.
             {kZeroingSampleSize, kClawEncoderIndexDifference, 0.0},
+            0.0,
           },
 
           {
@@ -266,6 +270,7 @@
             // Arm zeroing constants: left, right.
             {kZeroingSampleSize, kArmEncoderIndexDifference, 0.0},
             {kZeroingSampleSize, kArmEncoderIndexDifference, 0.0},
+            0.0, 0.0, 0.0, 0.0,
           },
           // TODO(sensors): End "sensor" values.