Big BIG refactor to make inventory use a model that's placed into the world, following a more sane MVC style.

inventory.hpp

@@ -0,0 +1,21 @@
+#include "dinkyecs.hpp"
+#include <unordered_map>
+
+namespace inventory {
+  using Slot = std::string;
+
+  struct Model {
+    std::unordered_map<Slot, DinkyECS::Entity> by_slot;
+    std::unordered_map<DinkyECS::Entity, Slot> by_entity;
+
+    void add(const Slot &in_slot, DinkyECS::Entity ent);
+    Slot& get(DinkyECS::Entity ent);
+    DinkyECS::Entity get(const Slot& slot);
+    bool has(DinkyECS::Entity ent);
+    bool has(const Slot& slot);
+    void remove(const Slot& slot, DinkyECS::Entity ent);
+    void remove(DinkyECS::Entity ent);
+    void remove(const Slot& slot);
+    void invariant();
+  };
+}