Transmitter rendering improvements.

Now uses a new, slightly modified ModelRenderer and ModelBox I adapted
to be able to selectively render faces. Also we can now turn off back-face
culling without any xyz-fighting.
Well, I don't know why the old way was broken but it's fixed now.
@Aidancbrady, why did osmium armour think it's made of diamond? I've
changed it because it was messing with the textures.