Add "Home Recall Stone"

[aravol]

Recipie for a stone keyed to the user's Spawn location. Rather than needing to be linked, this would always go to "home" (ie spawn point) for whoever used it - making it less powerful but possibly more useful than a standard Recall Stone.

[aravol]

Could this also be done by someone using their own Following Stone? Would make a possible recipe (see issue #9) significantly more useful