* fix banner support for 5.12+
- changed from .x to .obj format
- exported at 0.2 scale -> the base is still a bit larger
than a node but exporting smaller causes the base to levatate.
* fix pole
- moved up
- changed from .x to .obj format
* fix preview
by resizing the background the scaling works again.
Though lua_api.md promises that lower resolution textures
are upscaled to larger ones [see TEXMOD_UPSCALE]
* tweak formspec layout
