Add warning for colliding checkpoints

[Wuzzy]

There is a common mistake in trackmaking: At some point where the roads are close to each other, there is a checkpoint which somehow collides with the other road, too. You will notice it by a “wrong checkpoint” message when you pass this other road segment seemingly close to this checkpoint.

I want to have a warning when this happens.
The idea: Any checkpoint is “allowed” to collide with its own segment and the previous segment. A collision with any other track segment produces a warning. I assume that something is wrong when such a collision occours. The warning would be most of the time correct.

Edit: I have a addition to this idea: Also add a check for the start point and check wheather it collides with any checkpoint or is very close (<1 car length) to one.

[CryHam]

Right. Would be good.
Isn't easy to do (and not fast) if we want to check road segment geometry. I had to create whole road in bullet to have it, then I could check.
Generally I do it so when making tracks (and that's now expected) to drive the track few times and each time you notice a wrong check (while driving ok), you simply notice where (eg. using whole minimap with no zoom or rotation) then start editor, see whats wrong and fix it (either throw it out or put it elsewhere).