[mod] #320 #301 change check_public_key() behavior

    * create has_pubkey_checksum()
    * create is_pubkey_and_check()
    * change use of check_public_key in tx, balance and history commands.
    * use is_pubkey_and_check() in `id` command and solve #320
    * create tests for is_pubkey_and_check, has_pubkey_checksum() and check_public_key()

    * change imports in silkaj.money to prevent loop dependency