+ use btBroadphaseProxy::AllFilter to collide with static and dynamic rigidbodies in broadphase
+ enlarge aabb for softbody in broadphase, otherwise misses collisions (deformation is not updated in-time?)
Added very basic drawTriangle for btIDebugDraw, useful for basic softbody visualization.
Added btGjkEpa2, contribution by Nathanael Presson. Improved version of EPA penetration depth computation, more suitable for multi-core/SPU (less memory usage). Note: btGjkEpa2 is not enabled by default currently.