Rock Slide / Rubble / Blockage for Dungeons - freestanding

This is a combination of two other rubble types. I made the dead end freestanding, so people can use it on any 3D terrain, and used RobagoN's rubble to make it look more like a small rockslide out from the wall.

Since I tweaked it for my use, I thought I would make it available for everyone.

--Kev