General changes:
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* refactored all the code.
* replaced scrapers with api calls to speed up the info gathering process.
* updated documentation.
* removed parameter validations.
* added support for Wii U and 3DS games.
* improved test coverage.
* simplified the documentation of each method.
* separated api integration into different files.
Game Class changes:
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* unified everything into one class instead of one per platform.
* renamed genres to categories.
* moved features (dlc, amiibo, etc) into a dict.
* changed developers and publishers into a list of strings.
* added class to handle the generation of urls for each nintendo online eshop.
* improved organization for the rating values (ESRB, PEGI and CERO).