Features:
* Added a logbook and history properties to the fitted GASearchCV to make post-fit analysis
* Elitism = False now implements a roulette selection instead of ignoring the parameter
API Changes:
* Refactored the optimization algorithm to use deap package instead of a custom implementation, this causes the removal of several methods, properties and variables inside the GASearchCV class
* The parameter encoding_length has been removed, it's not longer required to the GASearchCV class
* Renamed the property of the fitted estimator from best_params_ to best_params
* The verbosity now prints the deap log of the fitness function, it's standard deviation, max and min values from each generation
* The variable GASearchCV._best_solutions was removed and it's meant to be replaced with GASearchCV.logbook and GASearchCV.history