Request: linemerge option to only merge when turn angle is small

[RectangleWorld]

It might be nice to merge two lines only when the resulting turn angle (as we pass from one curve to the next) is less than a given amount. This way line segments can be merged if they form a straight or nearly-straight polyline, but not if they create significant turns.

[abey79]

Yes. And also prioritise smaller turn angles when multiple merge options are available.