Post 1.0: Interior tags

[Tarius]

This is definitely a post 1.0 thing.

Add the ability for tags being added for various cells and by extension, their doors. Could be useful for searching the map at the later point without knowing the name of some place.

My main idea here though is to be able to have custom map markers that get applied according to a cell's tag. So if you have "cave" as a tag for an interior cell, the marker on the map for the doorway leading to that cell from the exterior would be whatever corresponds to the cave tag.