Switch to correct implementation

[Frollamma]

The current implementation of the Simplex Method is more similar to its "first form" (see Festa's slides, it is the simplest one where you invert the base matrix). The most important thing here is the output (not the efficiency), but you should consider switching to the exact implementation of the Full Tableau Simplex Method for efficiency and to get the code itself more "educative" and "coherent" with its