Use standard folders to store logs and database
Use standard folders to store logs and database

- make optional `database_file`, `log_file` and `api_log_file` args
- `appdirs.user_data_dir()` as default folder to store the database
- `appdirs.user_log_dir()` as default folder to store log files

monaparty/counterparty-lib,stefcrypto/counterparty-lib,CounterpartyXCP/counterparty-lib,F483/counterparty-lib,tokenly/counterparty-lib,coinwarp/dogeparty-lib,CounterpartyXCP/counterparty-lib,jarymoth/counterpartyd,monaparty/counterparty-lib,F483/counterparty-lib