AI improvement

From now on the AI cars can change lanes! They will do this when a slower car is approaching in front of them, or when they are on a lane that's about to disappear. While they will always move aside when their lane is about to disappear, they will check a few things before changing lane when a slower car is approaching:

• Is there a lane next to them? If so, is it about to disappear?
• Is there another car next to them?
• Is another car approaching in the lane next to them?
• Is another car overtaking them?
• ...

If they can't move aside, they will brake instead. Once they start moving aside, they won't stop until they are done.

Things to improve:

• Moving to the outside of a corner should be promoted, because it should be faster
• Make them change their mind once they notice moving aside is a bad idea (because you're blocking their lane for example)
• Sometimes they will clip through each other
• They can't fall down in the mountain stage and will clip through walls
• Small tweaks so they would make (even) better decisions.

You can also ram them off the road now. (To the side actually.)