[DQ_Kinematics.h, cpp] Added a static method to compute the line-to-line-angle-residual.

[juanjqo]

This PR adds a static method

DQ_Kinematics::line_to_line_angle_residual (const DQ& robot_line, const DQ& workspace_line, const DQ& workspace_line_derivative);

The method line_to_line_angle_residual() returns the residual term that satisfy vec(f(phi)_dot) = Jd*q_dot + residual, where f(phi)=dot(lz-l, lz-l) and Jd is the line-to-line-angle-jacobian.

[mmmarinho]

@juanjqo
Thanks! Please add the related minimal working example
https://github.com/dqrobotics/cpp-examples/pulls
and I'll get this pull request going.

[juanjqo]

@juanjqo Thanks! Please add the related minimal working example https://github.com/dqrobotics/cpp-examples/pulls and I'll get this pull request going.

@mmmarinho Added the required example!

dqrobotics/cpp-examples#13

[mmmarinho]

@juanjqo Please add a description to this pull request explaining what it does (even though the title is somewhat informative already).