GJK fix for https://github.com/bulletphysics/bullet3/issues/1703

In a nutshell, we added a more reliable check, based on if the origin is in the GJK simplex, to determine if we are really intersecting and need to run EPA.
See also "Real-time Collision Detection with Implicit Objects" by Leif Olvang
Todo: integrate the simplex penetration check directly inside the Bullet btVoronoiSimplexSolver
and remove this temporary code from libCCD
Note, for large differences in shapes, use double precision build!

src/BulletCollision/NarrowPhaseCollision/btGjkEpaPenetrationDepthSolver.cpp

@@ -33,8 +33,8 @@ bool btGjkEpaPenetrationDepthSolver::calcPenDepth(btSimplexSolverInterface& simp
 	(void)simplexSolver;
 
 	btVector3 guessVectors[] = {
-		btVector3(transformB.getOrigin() - transformA.getOrigin()),
-		btVector3(transformA.getOrigin() - transformB.getOrigin()),
+		btVector3(transformB.getOrigin() - transformA.getOrigin()).normalized(),
+		btVector3(transformA.getOrigin() - transformB.getOrigin()).normalized(),
 		btVector3(0, 0, 1),
 		btVector3(0, 1, 0),
 		btVector3(1, 0, 0),