Extra Rocks

Adds 2 new blocks; Cotswold and Greywacke.

Cotswold is crafted by 2x2 limestone in a grid, but unlike other stones they only get bricks, as used in real life.

Greywacke is a new stone that generates everywhere in the world like stone, deepslate, etc. It is also different to other stones in the way that is a perfect counterpart to stone but darker, comes with base, smooth and brick variants. (Stairs, slabs and walls too). For conformation, greywacke does not get a polished variant.

Also added stonecutter recipes for Siltstone, Slate and Chlorite after forgetting to add them in the last update...