* [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()