added pgs/jacobi cpu solver making the gpu rigid body pipeline work again (aside from running the solver on CPU)

opencl/gpu_rigidbody/host/btConstraintSolver.h

@@ -0,0 +1,52 @@
+/*
+Bullet Continuous Collision Detection and Physics Library
+Copyright (c) 2003-2006 Erwin Coumans  http://continuousphysics.com/Bullet/
+
+This software is provided 'as-is', without any express or implied warranty.
+In no event will the authors be held liable for any damages arising from the use of this software.
+Permission is granted to anyone to use this software for any purpose, 
+including commercial applications, and to alter it and redistribute it freely, 
+subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.
+*/
+
+#ifndef BT_CONSTRAINT_SOLVER_H
+#define BT_CONSTRAINT_SOLVER_H
+
+#include "BulletCommon/btScalar.h"
+
+class btPersistentManifold;
+class btRigidBody;
+class btCollisionObject;
+class btTypedConstraint;
+struct btContactSolverInfo;
+struct btBroadphaseProxy;
+class btIDebugDraw;
+class btStackAlloc;
+class	btDispatcher;
+/// btConstraintSolver provides solver interface
+class btConstraintSolver
+{
+
+public:
+
+	virtual ~btConstraintSolver() {}
+	
+	virtual void prepareSolve (int /* numBodies */, int /* numManifolds */) {;}
+
+	///solve a group of constraints
+	virtual btScalar solveGroup(btCollisionObject** bodies,int numBodies,btPersistentManifold** manifold,int numManifolds,btTypedConstraint** constraints,int numConstraints, const btContactSolverInfo& info,class btIDebugDraw* debugDrawer, btStackAlloc* stackAlloc,btDispatcher* dispatcher) = 0;
+
+	virtual void allSolved (const btContactSolverInfo& /* info */,class btIDebugDraw* /* debugDrawer */, btStackAlloc* /* stackAlloc */) {;}
+
+	///clear internal cached data and reset random seed
+	virtual	void	reset() = 0;
+};
+
+
+
+
+#endif //BT_CONSTRAINT_SOLVER_H