Building Indicators - City Labels

This package builds another level of logic on top of core indicators package to spawn and sort building indicators in the city labels. Additionally it instantiates and forces city labels to destroy indicators for empty slots that exists only in city labels context.

All indicators in grid-based view of city label have to be sorted in special way: First we list all idle building, then all buildings that are in construction right now and then empty slots. Inside of every sorting group buildings have to be sorted by their id. If any building is damaged, it keeps the same position, but visualizes damaged state in expected way.