Transition to djutils draw objects

[WJSchakel]

The following classes can be removed, and djutils draw objects can be used instead. If any feature is not yet present in djutils draw, this has to be implemented there before a complete removal.

• OtsPoint3d > Point2d/Point3d
• OtsShape > Polygon2d
• DirectedPoint > OrientedPoint2d/OrientedPoint3d
• Bounds > Bounds2d/Bounds3d

Furthermore, OtsLine3d will remain, but use a PolyLine2d and different elevation information underneath.

Other relevant classes are Bezier and Clothoid. These contain features not yet placed in djutils draw. In fact, they are quite different. For now it might be better to keep them, until the editor is more developed.

Any remaining dependency on the JTS library will also be removed.

[WJSchakel]

• OtsPoint3d, OtsShape, DirectedPoint and Bounds have been removed. Djutils classes are used instead.
• OtsLine3d remains, now with 2D underlying information.
• Dependency on jts library has been removed.
• OtsLine3d constructors based on jts library objects have been removed. They were not used.
• Many OtsLine3d methods now return a 2D result wrapped in a new OtsLine3d based on very similar methods in PolyLine2d from djutils on the underlying 2D line.
• PerceivedObject2d and PerceivedObject3d were removed, they were not used.
• Many slight changes in z-coordinates were removed as underlying data is now 2D. These z-coordinates changes had to do with drawing order. However, this has no effect as z-coordinate changes were already made in the animation objects.
• GTU-Lane bookkeeping required two changes. 1) Because orthogonal projection is strict in djutils (Point2d.intersectionOfLineSegments()), a point on the GTU path that is on the line to cross at the end of the lane, may not result in a found intersection. Therefore, if no intersection is found, each point in the path is projected on the line to cross, and if the fraction is within the range [0...1], and the distance is <1e-6, the point is considered to be crossed by the path. 2) Now that lanes are no longer forced to have the first/last segment in the direction of the node, fractional projection required the node directions at the endpoints. Otherwise the reference point could sometimes not be projected to any lane.
• Offset classes (Jts and Pk) have been removed.
• Unit tests and demos run succesfully.

What still remains is the following:

• XML still specifies 3D coordinates. The 3rd coordinate is currently ignored.
• In all cases (XML, OtsLine3d, possibly more) elevation information needs to be added as separate information.

How OtsLine3d returns its information remains to be seen. For example, the get(int) method now simply returns a Point2d from the underlying PolyLine2d.

[WJSchakel]

Rather than adding elevation data to OtsLine3d, it is instead added to Link. Therefore OtsLine3d has also been named OtsLine2d. The class remains a valid class in OTS as it add features over an PolyLine2d, most noteworthy the fractional projection.

Link now has the following methods:

• Length getElevation(Length)
• Length getElevation(double)
• double getGrade(Length)
• double getGrade(double)

Both elevation and grade can be requested at a length, or fractional length. The class CrossSectionElement has the same methods, and refers to the link. Note that in this manner, only the link needs to store elevation data (when relevant). Elevation data may also be null, in which case the elevation and grade are always 0.