more soft body preparations, moved some parts from Demo/SoftBody to src/BulletDynamics/SoftBody

moved Extras/ConvexHull/btConvexHull.* to src/LinearMath/btConvexHull.*
removed btCollisionObject::m_internalOwner, replaced it by m_internalType. This should not affect external API (it was clearly marked as internal)

src/BulletCollision/CollisionDispatch/btCollisionObject.h

@@ -66,8 +66,9 @@ protected:
 	///users can point to their objects, m_userPointer is not used by Bullet, see setUserPointer/getUserPointer
 	void*			m_userObjectPointer;
 
-	///m_internalOwner is reserved to point to Bullet's btRigidBody. Don't use this, use m_userObjectPointer instead.
-	void*			m_internalOwner;
+	///m_internalType is reserved to distinguish Bullet's btCollisionObject, btRigidBody, btSoftBody etc.
+	///do not assign your own m_internalType unless you write a new dynamics object class.
+	int				m_internalType;
 
 	///time of impact calculation
 	btScalar		m_hitFraction; 
@@ -100,6 +101,12 @@ public:
 		CF_CUSTOM_MATERIAL_CALLBACK = 8//this allows per-triangle material (friction/restitution)
 	};
 
+	enum	CollisionObjectTypes
+	{
+		CO_COLLISION_OBJECT =1,
+		CO_RIGID_BODY,
+		CO_SOFT_BODY
+	};
 
 	SIMD_FORCE_INLINE bool mergesSimulationIslands() const
 	{
@@ -189,14 +196,9 @@ public:
 	}
 
 	///reserved for Bullet internal usage
-	void*	getInternalOwner()
+	int	getInternalType() const
 	{
-		return m_internalOwner;
-	}
-
-	const void*	getInternalOwner() const
-	{
-		return m_internalOwner;
+		return m_internalType;
 	}
 
 	btTransform&	getWorldTransform()