Fix minor error with placement of route steps

[Pilot-Marc]

[Pilot-Marc]

The pivot point for each route step is 0.5 of the distance, and there's a comment that 0.5 is sometimes off and that the constant should be a settable property. The real fix should be to set the step location to the center of the line, which would coincide with the node's default pivot point.

[Pilot-Marc]

Note: This issue is fixed and will be available for review in the upcoming PR I'm preparing.