Trains

[Groneschild]

I Wasn't planning on making a pr, but here I am.

The first thing i did, was making a tool to make straight road connections. It looks better for both rail and highway infrastructure. I would like to enforce something like this for realistic looking rail.

The second thing are custom trains. The toolbox contains a train editor. Trains consist of rolling-stock. Anyone can add rolling-stock in base_mod/rollingstock.lua. I would like a similar thing for road vehicles.

Give me some help with the GUI related programming.

[CLAassistant]

All committers have signed the CLA.

[Uriopass]

Thank you for this (big!) contribution. I'm away for a week or so but I'll make sure to review when I come back!

[Uriopass]

Hey so I finally got to review. The code looks good but I have a bit of feedback about the UI. I guess it can probably be improved later on as yakui can take a bit of time to learn.

• Max Incline and Max Decline don't seem to be implemented yet, I think the icons should be disabled in the meantime.
• The straight road thingy is really good! Could probably be improved like in cities skylines to offer alignment with other roads, but the idea is great!
• The custom train editor is super cool but I think most players would want a set of pre-made trains. The UI is also quite raw, would need a lot more icons to be practical.
• You don't use rustfmt, it does look more ergonomic at times but I really like having a consistent style. You can disable rustfmt on blocks using the #[rustfmt::skip] annotation when you really need to.

Anyway all of these aren't blockers, the game is still in development after all and all these can be fixed later on. Still a good foundation! I'm going to merge this.