[invader-info] Show tag data usage of the map.

[Aerocatia]

It would be useful if invader-info would show how much of the tag data space is used in the map in the same way invader-build does after building.

It seems there is some error condition where Halo CE's tool.exe will build a map that goes over the tag data limit that probably involves indexed tags so it would be good to have some way of checking this.