Added landing voltage limit and test.

Change-Id: I0a74fba887c6f791c05ab6fd69c543678fcdb420
diff --git a/y2016/control_loops/superstructure/superstructure.h b/y2016/control_loops/superstructure/superstructure.h
index 23491bf..823e130 100644
--- a/y2016/control_loops/superstructure/superstructure.h
+++ b/y2016/control_loops/superstructure/superstructure.h
@@ -170,6 +170,11 @@
     ESTOP = 16,
   };
 
+  bool IsRunning() const {
+    return (state_ == SLOW_RUNNING || state_ == RUNNING ||
+            state_ == LANDING_SLOW_RUNNING || state_ == LANDING_RUNNING);
+  }
+
   State state() const { return state_; }
 
   // Returns the value to move the joint to such that it will stay below