Refactor model classes and provide to_dict method#160

horgh merged 7 commits intomainmaxmind/minfraud-api-python:mainfrom

greg/eng-841-easy-way-to-serialize-python-minfraud-model-objects-to-jsonmaxmind/minfraud-api-python:greg/eng-841-easy-way-to-serialize-python-minfraud-model-objects-to-jsonCopy head branch name to clipboard