Add support for playerfactions mod (#37)

Add faction indicator to HUD

api.lua

@@ -94,9 +94,13 @@ function areas:canInteract(pos, name)
 	for _, area in pairs(self:getAreasAtPos(pos)) do
 		if area.owner == name or area.open then
 			return true
-		else
-			owned = true
+		elseif areas.factions_available and area.faction_open then
+			local faction_name = factions.get_player_faction(area.owner)
+			if faction_name ~= nil and faction_name == factions.get_player_faction(name) then
+				return true
+			end
 		end
+		owned = true
 	end
 	return not owned
 end