* [pylint] Fix referencing undefined variable 'shutil'
* [pylint] Declare abstract LinkBase._send_apdu_raw() method as such
* [pylint] Fix float vs integer division in cards.py
* [pylint] Fix reference to undefined variable 'in_hex'
* [pylint] Mark abstract MagicSimBase class as such
* [pylint] Fix calling non-existing iteritems() of dict
* [pylint] Declare some fields in _MagicSimBase class
* [pylint] Mark abstract CardKeyProvider.get() method as such
* [pylint] fix non-existing 'res' in EF_CNL._encode_record_hex()
* Fix various mistakes around the CardADF <-> CardApplication dualism
* filesystem: fix various issues found by mypy
* filesystem: Avoid GPL header showing up in sphinx autodoc
* Use sphinx for generating documentation
* Add more documentation to the classes/methods
