TODO list

[Wohlstand]

• Child objects and sub-trees (include of ability to create groups of elements)
• Implement Z-Order
• Implement hand-dragging
• Smooth Scrolling [Optionally]
• Apply zoom factor to scrolling speed (but, re-align camera on zoom change to avoid a broken alignment)
• Implement the "animated items" render scheme where visible surface will be updated often.
• Replace QList container with PtrList to guarantee same pointer address in the memory. Instead of this, QSet was used inside of tree to hold dynamically allocated items.
• Allow polymorphism for PGE_EditSceneItem to allow different item types.
• Implement collision check callback called on move or mouse release by optional choose
• Implement background and foreground render callbacks (to fill empty surface with something or draw the grid or any overground meta-signs or animations)