Add algorithm to check the validity of model

Topic/dox

Bug correction in joint visitor

[C++] Added methods & algo to test if 2 configs are equivalent

Topic/planar integrate

Added methods in joints and algorithm working on Model to determine if two configurations are equivalent

Use correct package for hpp-model-urdf / Pinocchio comparisons

Handle 32 bits system

Update the Frame the part + expose new methods

The addFrame returns now a bool which its false when the frame already
exists.

[unittest] Fixed precision comparison test.

[Python] Updating Python tests to corresponds to the API 

[Python] Updating Python tests to corresponds to the API ( e.g we add frames for every link and joint we encounter in urdf )