* Avoid ambiguous definition during unity build on Windows
* Add missing include
* Add Qt6 to expressionparser
* Add Qt6 to nightcharts
* Replace forward define of QStringList with include <QStringList>
* Use toMSecsSinceEpoch
* Use setContentsMargins
Added a new feature for editing style sheets and variable colors and see immediately the result.
Made Qwt plots (and items) stylable.
Added icons, improved styling possibilities of QMinimizePanel, fixed minor bugs in RicThemeColorEditorFeature.