-make wandering hordes visible on overmap. (Code pulled from Reaper42's abandoned PR #6827)
When tearing off 0 HP parts, break them into pieces.
Merge pull request #7086 from belenos-/visible_hordes

Visible wandering hordes
Merge pull request #7118 from ianestrachan/break-torn-off-broken-parts

When tearing off 0 HP parts, break them into pieces.