Replacement Joint{Model,Data} with Joint{Model,Data}Variant in JointModelComposite

Add RNEA with external forces algo

Improve packaging

Fix alignment issue for the JointComposite

Update quaternions related operations

Hpp devel

update python's API + minor modifs on name conventions

[C++][eigen] Remove call to eigen method hasNaN to ensure compatibility with eigen 3.0.5. Provide our own implementation

Topic/joint composite

[C++][unittest] Fix computations in jointcomposite::calc() + reworked unittest (comparison of R3xSO3 (either two joints with no inertia between them or Jointcomposite))

[C++] Removed default parameters for bounds when adding joint and created an overloaded method instead. Switched the order for addJoint method (put the default valued argument at last position)