Stone rubble block

[Wahazar]

I propose to introduce stone rubble block, with texture similar to cobblestone, just less regular (two variants would be welcome).

Such block should have stability similar to gravel or sand.

3x3 stones would craft 2 such blocks. Breaking (with pickaxe or hand) would give 3...4 stones back.

In case of cave-in (if enabled), regular stone falling would become rubble stone block, also nearby cracked stone would be converted to rubble stone and fall if updated.

There are 3 reasons backing of such proposal:

1. cave-ins are not very immersive now, no way that uniform stones are falling creating new uniform layer of stones (there are also bugs with teleporting stones trough celling). With rubble stones, cave-ins are more plausible, and what is more important - player have chance to recover from rare but annoying case, when his pick was broken.

2. Possibility of making blocks from stones, for escaping from mining wells.

3. Early nice stone block for floors, without need for clay.