* changes:
[apps] create a class variable box lead cell
[apps] Ensure const methods when needed in node class
[apps] use toolbox leaf cell in the toolbox controller
[apps] create a class toolbox leaf cell
[apps] Improve the drawing of boxes (variable and toolbox)
[escher] enable stack view controller to have different stack view colors
[escher] Change palette names to make them consistant
[apps] enable node navigation controller to use different cell types (implemented by its subclasses)
[escher] Correct int comparison issue in text field
[escher] improve stack view drawing
[escher] add default constructor for text menu list cell