[1.1.0] Crash using LuaGuiElement.bring_to_front()

[Choumiko]

Calling LuaGuiElement.brong_to_front() during on_configuration_changed yauses a hard crash.

To reproduce:
- add the 2 attached mods
- load the attached save (it didn't have the mod previously, but has all techs researched via cheat)

Starting a new save with the mod and then using cheat and opening the gui (with the shortcut button or Ctrl + L) the call to bring_to_front() works.

[Rseding91]

Thanks for the report. It's now fixed for the next release.