Fixed Level Crossing Animations

I found it annoying how the level crossing barriers would close so slowly that the train was already passing before they had closed, and how the barriers would open so slowly that cars started moving and clipping through them. This mod changes the animations to fix that. Barriers now close and open faster and with less delay, meaning they actually close before the train passes and open before traffic starts moving, which obviously looks better and more realistic. The crossing bell sound effect has been replaced and now lasts longer as well, stopping once the barriers have been fully closed for a few seconds. It's now based on an English level crossing bell, but I think it sounds suitably generic for all crossings. I've also changed how the traffic light on the European crossing works. Instead of being a red/green traffic light, it shows an amber warning light for a couple of seconds before the gates start closing, then shows a flashing red light. This more closely matches the European crossings I have seen. The fixed animations and warning bell apply to all crossing types in all regions.