Add new constructor to Vector class based on radius and angle.
When adding ducks in duckamtic, do not use the component index directly.
Get the index by name.
When calculating the reverse of a BlinePoint, use its internal reverse
member instead of figure out externally.
Refactor class BLinePoint:
1) Replace split_tangent by the combination of split_tangent_ragdius and
split_tangent_angle.
2) Add new private members to retrive the combination of both flags for
full split or full merged
3) Add two new private members to store the tangent2 to return for the
possible split flags combinations (tangent2_radius_split and tangent2_angle_split)
4) New private member function update_flags to update new flags from 2)
5) New private member to update the tangent2 accordingly to the flags.
6) Update callbacks to BLinePoint members where applicable.