Entrance camera has incorrect pitch

[madebr]

When entering a new race, the camera has the wrong pitch. It should point downwards towards the car.

Workaround: Remove all opponents by setting OPPONENT_COUNT to 0

https://github.com/dethrace-labs/dethrace/blob/80f5fceff92e908d47a30567b0a34c26e8ce030c/src/DETHRACE/constants.h#L297

Another workaround (fake fix): Modify if (swoop) to if (0)

https://github.com/dethrace-labs/dethrace/blob/3980d9e9c92259770135f8d9a3428b2fb4c928c2/src/DETHRACE/common/car.c#L4844

The root cause is the missing implementation for multiple cars: all cars (except the player) have coordinates (0.f, 0.f, 0.f). Because the entrance camera will point at the average of these positions, it will point at (0, 0, 0), not the real location.