add improved btGeneric6DofSpring2Constraint, thanks to Puhr Gabor and Tamas Umenhoffer!

improved the new demo testbed (work-in-progress)
add basic Lua demo, import URDF test, STL import, obj import

Demos3/bullet2/LuaDemo/LuaPhysicsSetup.h

@@ -0,0 +1,43 @@
+#ifndef _LUA_PHYSICS_SETUP_H
+#define _LUA_PHYSICS_SETUP_H
+
+#include "../Demos/CommonPhysicsSetup.h"
+
+//we don't derive from CommonRigidBodySetup because we
+//create and own our own dynamics world (one or more)
+//at run-time
+struct LuaPhysicsSetup : public CommonPhysicsSetup
+{
+
+    LuaPhysicsSetup(class SimpleOpenGL3App* app);
+    virtual ~LuaPhysicsSetup();
+
+	class btDefaultCollisionConfiguration* m_config;
+	class btCollisionDispatcher* m_dispatcher;
+	class btDbvtBroadphase* m_bp;
+	class btNNCGConstraintSolver* m_solver;
+	class btDiscreteDynamicsWorld* m_dynamicsWorld;
+    class SimpleOpenGL3App* m_glApp;
+
+	virtual void initPhysics(GraphicsPhysicsBridge& gfxBridge);
+
+	virtual void exitPhysics();
+
+	virtual void stepSimulation(float deltaTime);
+
+    virtual void    debugDraw();
+
+	virtual bool pickBody(const btVector3& rayFromWorld, const btVector3& rayToWorld);
+	virtual bool movePickedBody(const btVector3& rayFromWorld, const btVector3& rayToWorld);
+	virtual void removePickingConstraint();
+
+	virtual void syncPhysicsToGraphics(GraphicsPhysicsBridge& gfxBridge);
+
+	virtual btRigidBody*	createRigidBody(float mass, const btTransform& startTransform,btCollisionShape* shape, const btVector4& color=btVector4(1,0,0,1));
+
+	virtual btBoxShape* createBoxShape(const btVector3& halfExtents);
+
+};
+
+
+#endif //_LUA_PHYSICS_SETUP_H