Added "safe" version of bones

Survival mode has bones to facilitate the dropping of your inventory when you die. But on a build server, bones can be used for creating cool graveyards. When building, having bones nodes gives us more nodes to work with. This commit adds a version of bones to the build game that does not cause you to lose your items.

All credit for the code goes to PilzAdam. This is just a gutted version of his survival bones.