Make the internal control loop type a template argument.

We need this to switch the statespace loops over to floats for the
pistol grip controller.  Also, plumb it up to the control loop writer.

Change-Id: I9e12d8d69ea7027861b488c06b45f791c71c4eb3
diff --git a/y2017/control_loops/superstructure/shooter/shooter.cc b/y2017/control_loops/superstructure/shooter/shooter.cc
index 03abd99..f8bfecf 100644
--- a/y2017/control_loops/superstructure/shooter/shooter.cc
+++ b/y2017/control_loops/superstructure/shooter/shooter.cc
@@ -23,7 +23,8 @@
 // TODO(austin): Pseudo current limit?
 
 ShooterController::ShooterController()
-    : loop_(new StateFeedbackLoop<4, 1, 1, StateFeedbackHybridPlant<4, 1, 1>,
+    : loop_(new StateFeedbackLoop<4, 1, 1, double,
+                                  StateFeedbackHybridPlant<4, 1, 1>,
                                   HybridKalman<4, 1, 1>>(
           superstructure::shooter::MakeIntegralShooterLoop())) {
   history_.fill(0);