Project structure and codebase in development, it promise to grow. This section would help with understand what is going on, before you start to work with code.
* To access any children features, deeper or higher than 1th level of current class, use delegation methods (actions, getters and setters)
* One file - one class. If the file requires additional (GTK) component, this component should be placed at similar folder with same name as parent filename. So we have simple hierarchy navigation logic - from app to window, from window to it container, etc.
* At this moment, all constants named with uppercase, const everything that not mutable
* App class tables in database wanted to store user data between app sessions and must contain only fields that related to this class (e.g. private and public variable values); also may contain primary key fields, to their parent (table) according to the namespace hierarchy