Tune turret for real

Add in friction compensation and tune the controller a bit.  Fix a poor
velocity estimate.

Change-Id: I153b659bf92d5f34f0e8f59fda34e3c693e41d6a
diff --git a/y2020/constants.cc b/y2020/constants.cc
index f0610a0..7fe24bf 100644
--- a/y2020/constants.cc
+++ b/y2020/constants.cc
@@ -107,10 +107,10 @@
       intake->zeroing_constants.measured_absolute_position =
           1.42977866919024 - Values::kIntakeZero();
 
-      turret->potentiometer_offset =
-          5.52519370141247 + 0.00853506822980376 + 0.0109413725126625;
+      turret->potentiometer_offset = 5.52519370141247 + 0.00853506822980376 +
+                                     0.0109413725126625 - 0.223719825811759;
       turret_params->zeroing_constants.measured_absolute_position =
-          0.251065633255048;
+          0.547478339799516;
       break;
 
     case kPracticeTeamNumber: