Helper debug splines for easier work with gradients 1.0.1

A pack of helper splines that make it easier to see if there is a gap between two splines on Z axis. This is useful if you have terrain splines or curbs that use gradient.

When I work on my maps I often need to use gradients on splines (there are a lot of hills) and sometimes it's really hard to see if there is a gap between two parallel splines or when a spline with gradient is joining the main road. Then I came up with an idea to add "walls" on each side that will go down 2m and then I will able to see the pink color and help me align these splines as close as possible. The greatest thing is that I will know how much gap is there and if it's tolerable or not.

In the pack I followed standard practice in OMSI and used 0.1 as lowest point of the splines, so both curbs and asphalt splines will start at 0.1. But you can easily adjust this.

The pack includes:
Asphalt splines - 0.5m, 1m, 1.5m ... 10.5m (0.5m steps) - I will add more widths soon (I plan to include up to 30m).
Curbs - just a curb spline (based on Simple Streets) and curbs with sidewalks (0.5m, 1m ... 3m). I'm aware the texture of the sidewalk isn't ideal in some splines, but after all that is not the purpose of this pack so ...

One thing to note is that the main texture of the spline really doesn't matter, for example: if you have a zebra spline that is 4m, you can use the 4m debug spline. And when you are done with aligning just replace it back to your zebra spline.

You can also leave these splines on your map, but I don't recommend it. First, sometimes the pink could be visible (otherwise nobody would notice that gap) and secondly - the debug walls will just add more meshes so poor optimization.

I hope someone finds this useful. You can also apply this technique on any of your splines too!