LMarbles can not be closed when executed in fullscreen

affected: 0.4.3RC1 & 0.4.1

When you try to close the game while being fullscreen, it will keep running in windowed mode without painting any content into the window and spam endlessly:
(this log from 0.4.1, line number may have changed since then, text is same)

fixme:(dll/directx/wine/wined3d/surface.c:2587) Cannot find a conversion function from format WINED3DFMT_B8G8R8X8_UNORM to WINED3DFMT_B5G6R5_UNORM.