Sound mod for v1.2

This mod adds personalized sound for Sport Cars Traffic Pack by TrafficManiac v1.6

The modified sii files includes also:
- minor changes in max_speed (increased on most of the cars)
- some models are allowed to appear parked
- added spawn_ratio between 0.1 and 0.5 (not active if country spawn file is used)

This mod can be used in ETS2 and in ATS (the pack is similar)