set hull from vertex format

The user can create a convex hull from a vertex format, not directly from a list of vertices. That's interesting because in some 3D engines convex hulls are typically created from a render mesh that might structure a vertex in different ways in the memory.

examples/testbed/tests/convex_hull.h

@@ -81,7 +81,7 @@ public:
 			m_points[m_count++] = p;
 		}
 		
-		m_hull.Set(m_points, m_count);
+		m_hull.Set(sizeof(b3Vec3), m_points, m_count);
 		assert(m_hull.faceCount > 0);
 		m_selection = m_hull.GetSupportFace(b3Vec3_z);
 	}