Allow setting if a SpiderLegPrototype rotates with its connected body or not

[Izzabelle]

I was experimenting with the early stages of a mod that lets you "domesticate" pentapods, and found out that whether the leg rotates with the body or not is hardcoded depending on if it's a SpiderVehiclePrototype or SpiderUnitPrototype. More control over this would be excellent, as I can see plenty of cases where people would want either spider vehicles with legs that rotate with the body or spider units with fixed leg placement.

My personal suggestion is to let each leg individually define if it rotates or not, as that'd allow for some very fancy looking units.
Potentially there could even with some sort of rotation_rate value that lets you precisely control the rotation. A value of 1 makes it follow the body, 0 makes it stay in place, 2 makes it twice as fast and -1 goes reverse.

I understand that might be incredibly wishful thinking since I have no idea how the source code is set up. But even just a true/false on the spider_engine itself would be good enough for what I'm doing.

[MrSmoothieHuman]

+1

[berggen]

Mecha dogs from mods? +1