Mark all metatables as consts

Fixing the Likka no following bug

Author: girvel

mech/ais/combat.lua

@@ -142,5 +142,5 @@ methods.observe = function(self, entity, dt)
   end
 end
 
-Ldump.mark(combat_ai, {}, ...)
+Ldump.mark(combat_ai, {mt = {}}, ...)
 return combat_ai

state/init.lua

@@ -281,5 +281,5 @@ methods.in_combat = function(self, entity)
   return State.combat and Table.contains(State.combat.list, entity)
 end
 
-Ldump.mark(state, {}, ...)
+Ldump.mark(state, {mt = "const"}, ...)
 return state