Grass Slabs and Stairs

With an emphasis on looking pretty.

This mod adds slabs and stairs for dirt and grass in MTG. It also adds connected grass blocks and slabs and stairs for those. If you have moreblocks installed then it also adds grass slopes for smooth hills and stuff.

Extra nodes and texture modifiers are used to make the textures consistant and pleasant to look at. Compatible with other textuere packs.*

* 16 by 16 textures only. see https://github.com/luanti-org/luanti/issues/13501#issue-1708472539

Integration with other games is welcome. Feel free to make pull requests.