Made stack action a lot closer to working.

Change-Id: Ieb0e0c1acfd7082667e3eed7314a53bf923f34ee
diff --git a/frc971/actors/stack_action.q b/frc971/actors/stack_action.q
index 6ef4fd8..caa8abf 100644
--- a/frc971/actors/stack_action.q
+++ b/frc971/actors/stack_action.q
@@ -2,12 +2,18 @@
 
 import "aos/common/actions/actions.q";
 
+// Parameters to send with start.
+struct StackParams {
+  // Angle to move the claw to when picking up.
+  double claw_out_angle;
+};
+
 queue_group StackActionQueueGroup {
   implements aos.common.actions.ActionQueueGroup;
 
   message Goal {
     uint32_t run;
-    uint32_t params;
+    StackParams params;
   };
 
   queue Goal goal;