Claw gets further when zeroing.

- Claw now roughly finds out where it is.
- The state feedback loop now has a Correct method which takes the
  measurement to use.
diff --git a/frc971/constants.cc b/frc971/constants.cc
index 815bebb..14745b5 100644
--- a/frc971/constants.cc
+++ b/frc971/constants.cc
@@ -53,7 +53,7 @@
             true,
             control_loops::MakeVClutchDrivetrainLoop,
             control_loops::MakeClutchDrivetrainLoop,
-            1.0,
+            0.5,
             0.1,
             0.0,
             1.57,
@@ -72,7 +72,7 @@
             false,
             control_loops::MakeVDogDrivetrainLoop,
             control_loops::MakeDogDrivetrainLoop,
-            1.0,
+            0.5,
             0.1,
             0.0,
             1.57,