debug overlay

[kianzarrin]

printing bezier, position, and direction in log does not make things very helpful(which is what we are doing now). So I created this simple framework for debug overlay. there is also:

• some extensions for simple overlay (Highlight.cs was too complicated for our simple debugging needs).
• usage in one place to test it.

Test: select a vehicle near junction/end and observe its transition bezier information This is draft because it needs my prev PRs for testing.

[kianzarrin]

this is pic from my experimental code.

[kianzarrin]