Move system initialization in systems.c, properly delete all entities when unloading map

game/components.c

@@ -3,6 +3,8 @@
 #include "unit_ai.h"
 #include "unit_actions.h"
 
+ECS_TAG_DECLARE(GameEntity);
+
 ECS_COMPONENT_DECLARE(Resource);
 
 ECS_COMPONENT_DECLARE(TilePosition);
@@ -38,6 +40,8 @@ ECS_TAG_DECLARE(Workable);
 ECS_TAG_DECLARE(Attackable);
 
 void initComponentIDs(ecs_world_t *ecs) {
+    ECS_TAG_DEFINE(ecs, GameEntity);
+
     ECS_COMPONENT_DEFINE(ecs, Resource);
 
     ECS_COMPONENT_DEFINE(ecs, TilePosition);