Havok: Fix class/struct mismatches

lib/hkStubs/Havok/Physics2012/Dynamics/World/hkpWorld.h

@@ -35,30 +35,30 @@ class hkpEntityListener;
 class hkpIslandActivationListener;
 class hkpIslandPostCollideListener;
 class hkpIslandPostIntegrateListener;
-class hkpLinearCastInput;
+struct hkpLinearCastInput;
 class hkpMtThreadStructure;
 class hkpMultithreadConfig;
 class hkpPhantom;
 class hkpPhantomBroadPhaseListener;
 class hkpPhantomListener;
 class hkpPhysicsSystem;
-class hkpProcessCollisionInput;
+struct hkpProcessCollisionInput;
 class hkpRigidBody;
 class hkpSimulation;
 class hkpSimulationIsland;
 class hkpTypedBroadPhaseDispatcher;
-class hkpViolatedConstraintArray;
+struct hkpViolatedConstraintArray;
 class hkpWorldDeletionListener;
 class hkpWorldExtension;
-class hkpWorldGetClosestPointsCommand;
+struct hkpWorldGetClosestPointsCommand;
-class hkpWorldLinearCastCommand;
+struct hkpWorldLinearCastCommand;
 class hkpWorldMaintenanceMgr;
 class hkpWorldOperationQueue;
 class hkpWorldPostCollideListener;
 class hkpWorldPostIntegrateListener;
 class hkpWorldPostSimulationListener;
-class hkpWorldRayCastCommand;
+struct hkpWorldRayCastCommand;
-class hkpWorldRayCastOutput;
+struct hkpWorldRayCastOutput;
 
 namespace hkWorldOperation {
 struct BaseOperation;