Drawbackground in STKListBox is not working

[spongythecake]

Part of GUIEngine code. An underlying listbox implementation was introduced by developers which overrides the Irrlicht version. Set background is a common feature to change the color of lists, however the STK versions has the option turned on but commented code disables it from it's potential.

stk-code/src/guiengine/skin.cpp

Line 2067 in db2cc69

//drawBoxFromStretchableTexture(widget, rect,