Fixes

[david-strahl]

• [ ] Settings uses Quicksettings for very simple task, unnecessarily including another library. Better drop it.
• [ ] Settings is streamlined for global settings. Update for multiple settings panels, too.
• [ ] Legend generation and color assignment are not separated. Do this, so that the color scale can be changed after the legend was generated.
• [ ] View system is not based on classes.
• [x] Tree nodes mix data, layout, and other fields and is not based on classes.