[GeoLib] Corrected implementation of check if Polyline is in Polygon.

The check if a polyline is in a polygon is needed within the SimplePolygonTree.
> have you considered a case polylines intersect at existing points so that you don't need to create new one?

The function ```lineSegmentIntersect()``` only computes the intersection. It does not check if the intersection point already exists. This is done later on (see line 450).

> How about a case more than two polylines intersect at one point (only one point should be created in this case)? 

This case should be handled in a correct way.