Better wall 3D inventory icon

[Wuzzy2]

The wall icon does not really look like a wall. It should have a proper 3D model.

There are 2 ways to fix this:

• Either draw those manually (e.g. Blender render)
• Or wait until Minetest allows to set custom nodeboxes or meshes for the inventory image or wieldhand.

The latter option requires an engine change.

[azekillDIABLO]

the top 1 seems okay.