Extended Policar to Sport Adapter

A few minor modifications. I added the slots on the side of the track for the Policar track clips at that end. Also, the length was extended so that the track surface (not counting the connecting tabs) was 185mm long. This way, an adapter at each end of a Scalextric Sport Digital double lane changer would add up to the same length as 2.5 Policar straigts, so make it easier to plan and fit into a Policar layout.