Refactor code basis

[igormcsouza]

The package uses a lot of functions and types. It might be better to change that to be classes so they can be converted into nice design patterns.

[igormcsouza]

I was thinking of splitting the model and the heuristic... the Mathematic Model will have an optimizer function (or multiple) and the constraints, as well as the function to generate random samples (or maybe based on some greedy algorithm)