[fix][mbs_part] threshold now taken into account during part see issue #157

Closes #157

See merge request !256

taking nstate = 0 into account in integrators (no independant joints) see issue #159

Closes #159

See merge request !257

Free MbsDirdyn->MbsDirdynOptions->compute_Qc in function mbs_delete_dirdyn

Closes #160

See merge request !255

Kalman dcpt

See merge request !254

small changes related to the type for mult_dmat_0. In addition, the error message has been disactivated.

schur dcpt function include now an option to choose whether or not the eigenvalues should be rearranged.

modification in modal module: 1- animation options (speed,dt and t) are added. 2- the normalization of the eigenvector is now performed also when Nux>0 (it is done based on qu and ux BUT NOT on the qud, as speeds do not appear in the anim eigenvector).

small error correction in mbs_linearipk. So that the input from x_star is properly restored after linearization.
Important in the case of a linearization with respect to a non q,qd,ux value.

- addition of argument for format in print and save_dmat function. This is done through the use of the specific subfunction print_format_... and save_format_...
- small typo correction for mult, ...

addition of two new functions for the lut... with the help of new function in the useful_function file

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Lqr development

See merge request !250