Robust intersection

Added line intersector for 2D.
Predicate is computed robustly, based on orientation test. Support COLLINEAR cases too.
For more information about intersection predicate computation see to code please (getCollinearCode mainly).

Computation of intersection point is based on homogeneous coordinates, so approximately, but robustly - use BigDecimal witch round off to double on finish of computation.

TODO: snap rounding.