Feature/lookahead controls

[calbaker]

see

altrios/altrios-core/src/train/speed_limit_train_sim.rs

Lines 596 to 600 in c908793

	// The code below is wrong, but the idea is that you need to make two vectors:
	// - one with offset and elevation for the entire timed_path
	// - one with offset and speed_limit for the entire timed_path
	// This approach might work, but it's not 100% thought through. For example, it doesn't account for train length.
	// It might be worthwhile to check if each element in the PathTPC is long enough to enable this without modifiyng the code.