forked from SteamWar/SteamWar
/hullhider hides the inside of the build area hull of a region from the players who toggle it, like the hull hider of a fight. Each region gets its own hull while somebody uses it; it is rebuilt every time somebody enables it, as WorldEdit and Axiom changes do not update it. /techhider, /xray and /hullhider exclude each other per player and region. Which players may see the hull contents is now decided by Viewers, a sealed class with HiddenByDefault (fight) and VisibleByDefault (bau). Added players are stored in a set; isViewer alone defines what being added means.