Version 0.10.281

+ stoppark module now conforms to PEP 396. Appropriate changed were applied to setup.py.
+ Implemented `check` method for CardPayment.
+ Added extensive documentation to interface module.
+ Minor caption changes in login.ui.
+ Added some docstring to once_payable module.
+ tariff.Tariff.create now handles more exceptions.
+ db.get_tariffs now filters incorrect tariffs.