Preparation for version 3.0.0

[lisphilar]

We have many deprecated classes and methods. It will be good to remove them for maintence this library.

Additionally, some internal classes will be renamed (CleaningBase will be renamed to _CleaningBase as an example). Because many classes are registered at the top bel class, users may be confused.

[lisphilar]

Scenario.records(variables=None) and Scenario.simulate(variables=None) will select Confirmed/Recovered/Fatal.

[lisphilar]

Scenario.records_diff() will accept the same change of default values.