Templatize interpolation table to make it more geneirc.

Change-Id: I7da0698486775b3e2482fa99fa172d6e1b6028ac
diff --git a/y2017/constants.h b/y2017/constants.h
index c6aa70c..bf25990 100644
--- a/y2017/constants.h
+++ b/y2017/constants.h
@@ -127,7 +127,15 @@
 
   double vision_error;
 
-  ::frc971::shooter_interpolation::InterpolationTable shot_interpolation_table;
+  struct ShotParams {
+    double angle;
+    double power;
+    double indexer_velocity;
+
+    static ShotParams BlendY(double coefficient, ShotParams a1, ShotParams a2);
+  };
+
+  ::frc971::shooter_interpolation::InterpolationTable<ShotParams> shot_interpolation_table;
 };
 
 // Creates (once) a Values instance for ::aos::network::GetTeamNumber() and