Inventory and lighting improved, now to get ready for going down a level and that's most of the game loop working.

inventory.cpp

@@ -14,6 +14,10 @@ namespace components {
     items.push_back(new_item);
   }
 
+  bool Inventory::has_item(size_t at) {
+    return at < items.size();
+  }
+
   InventoryItem& Inventory::get(size_t at) {
     dbc::check(at < items.size(), fmt::format("inventory index {} too big", at));
     return items[at];