Big work-in-progress refactoring of the constraint solver:

1) Add fast branchless SIMD support for constraint solver (Windows only until we get other contributions).
See resolveSingleConstraintRowGenericSIMD in Bullet/src/BulletDynamics/ConstraintSolver/btSequentialImpulseConstraintSolver.cpp
resolveSingleConstraintRowGenericSIMD can be used for all constraints, including contact, point 2 point, hinge, generic etc.

2) During this refactoring, all constraints support the obsolete 'solveConstraintObsolete' while we add 'getInfo1' and 'getInfo2' support.
This interface is almost identical interface to Open Dynamics Engine, to make it easier to port Dantzig LCP solver.

3) Some minor refactoring to reduce huge constructor overhead in math classes.

src/BulletDynamics/ConstraintSolver/btSliderConstraint.h

@@ -126,7 +126,13 @@ public:
     btSliderConstraint();
 	// overrides
     virtual void	buildJacobian();
-    virtual	void	solveConstraint(btScalar	timeStep);
+    virtual void getInfo1 (btConstraintInfo1* info);
+	
+	virtual void getInfo2 (btConstraintInfo2* info);
+
+    virtual	void	solveConstraintObsolete(btSolverBody& bodyA,btSolverBody& bodyB,btScalar	timeStep);
+	
+
 	// access
     const btRigidBody& getRigidBodyA() const { return m_rbA; }
     const btRigidBody& getRigidBodyB() const { return m_rbB; }
@@ -202,7 +208,7 @@ public:
 	btScalar getAngDepth() { return m_angDepth; }
 	// internal
     void	buildJacobianInt(btRigidBody& rbA, btRigidBody& rbB, const btTransform& frameInA, const btTransform& frameInB);
-    void	solveConstraintInt(btRigidBody& rbA, btRigidBody& rbB);
+    void	solveConstraintInt(btRigidBody& rbA, btSolverBody& bodyA,btRigidBody& rbB, btSolverBody& bodyB);
 	// shared code used by ODE solver
 	void	calculateTransforms(void);
 	void	testLinLimits(void);