[WIP] Fix code generation for rock base-types

[AlexanderFabisch]

• Static methods of a class 'CLS' will now have the prefix 'CLS_', e.g. 'CLS_static_method()'.
• Fixed typo in interface of Config: renamed all occurences of 'decleration' to 'declaration'. In particular, the method Config.add_decleration() has been renamed to Config.add_declaration().

TODO

• check test coverage
• refactor
• update version (this PR contains breaking changes)