Allow all widgets to be closed, still in dev
Merge branch 'workshop' into GuiLayout

Conflicts:
	Global/GitVersion.h
	Gui/Gui.cpp
	Gui/ProjectGui.cpp
Bug fix : serialised backdrops wouldn't recover their name
Bug fixes:
- RenderRoI: if getRoD returns a null rod, returns a null image, do not
continue
- Fixed a bug when restoring the layout of the GUI
Merge branch 'GuiLayout' into workshop

Conflicts:
	Global/GitVersion.h