Extract faces directly from btConvexHullComputer (in initializePolyhedralFeatures), instead of reconstructing them, thanks to Josh Klint in #1654
PyBullet: use initializePolyhedralFeatures for convex hulls and boxes (to allow SAT)
PyBullet: expose setPhysicsEngineParameter(enableSAT=0 or 1) to enable Separating Axis Test based collision detection for convex vs convex/box and convex versus concave triangles (in a triangle mesh).