Integrate IDyM for floating base with UI

Integrate Inverse Dynamic Model computation for robots with floating
base with the UI.
Rename the function that performs the recursive Newton-Euler algorithm
to `composite_newton_euler()`.
Add `compute_idym()` and `compute_ddym()` methods to `Robot` class.
Rename `Newton_Euler()` to `default_newton_euler()`

Rename `Newton_Euler()` to `default_newton_euler()`
Update all function calls accordingly.
Add `compute_pseudotorques()` method to `Robot` class

Add `compute_pseudotorques()` method to `Robot` class.
Update calls from the UI accordingly.
Start Direct Dynamic Modelling for floating base robots
Complete Direct Dynamic Model for floating base robots
Fix symbol replace call with the correct function

Call `replace()` instead of `mat_replace()` for `h_inv` since it is a
scalar.
Integrate DDyM for floating base with UI

Integrate Direct Dynamic Model computation for robots with floating base
with the UI.
Update `compute_ddym()` method in `Robot` class accordingly.