check_public_key() was used for money- and wot- related commands that have differend needs.
    * remove check_public_key()
    * create is_pubkey_and_check(), check_pubkey_format() and validate_checksum()
    * create related tests
    * modify tx, balance and history commands.
    * use is_pubkey_and_check() in `id` command and solve #320

    * change imports in silkaj.money to prevent loop dependency

    * gets a pubkey in for input
    * returns the checksum

Sébastien DA ROCHA authored 6 years ago and Moul committed 6 years ago

- move main in `bin/silkaj`.
- fix variable naming.
- remove requirement.txt
- add setup.py with Python 3.7 compatibility: #98.