- change bl_info["support"] to COMMUNITY. because Blender do not support TESTINg anymore.
- now plugin should be installed in addons folder, not addons_contrib, due to blender changes.
- remove the reference about mesh.polypons.loop_total. because it is readonly now. (blender 3.6 changed)
- change uv assign method. use new properties instead. (MeshUVLoop is deprecated in blender 3.5 and removed in blender 4.0)
- update README to keep update with plugin design
* refactor Select by Virtools Group section
* add material preset function description
- fix issue about flatten uv may get zero base vector.
- update elements adder menu.
- bump up version to 3.1
- add tunnel section creation and re-organise rail creation menu.
- allow duplicated elements (Nong xxx) creation for some special, such as Fan and Extra Point.
