[fredroy]

fixing some shenanigans to allow clang-msvc to compile sofaimgui
finding this issue without ai would have been .... complicated 💀

factoryMap was an inline static data member, filled by the dw_* globals of ImGuiDataWidget.cpp during static initialization.
With clang-cl, the initializer of an inline variable is emitted in a separately ordered CRT section, so the dw_* initializers could 
run before the map was constructed, crashing with an access violation when loading SofaImGui.dll ("DLL initialization 
routine failed").