Update rotation matrices classes.
Add binary operations for rotation matrices + multiplication type finding.
Fix namespace problems with std, and one wrong output stream to cout.
Introduces new files organization for joints + test for transform.
joint.hh now is the entry point for the other joints files.
Introduces rotTsymmetricMatrix method for crba in optimized rotation matrix.
Add binary operator and multiplication operator for rotation matrix.
Add specialized mulMatrixTransposeBy for rotation matrices about X, Y and Z axis.
Add more tests on rotation matrices.
Add xt_type and sxp_type to link description.
Add automatic derivation of xt_type and sxp_type in robotbuilder.
Extract the right joint type from the URDF file.
Fix return status when adding link.
Fix minor typos.
Fix joint_F initialization issue.
This commit allows a proper initialization  of the robot models.
Proper initialization of joints about x-y-z axis and free flyer.