Feature request: Make EditorGUI controls compatiable with Graphics2D and UserInterface

[MaxBelleville]

I am working on a project using the sample GUI example as a base. See that you built a good amount of compontents for the editor including the save/open file dialog that was in base Irrlicht. I can make my own version of these componets using the UI creator from the editor.

However it would be a nice quality of life feature if you make the EditorGUI controls can be called/created via using the CUIElement/CUIContainer or UIBase clasesses. Thanks in advanced.