Save existing vehicles if we had to load player (#22)

plugin/src/main/java/com/lishid/openinv/OpenInv.java

@@ -465,6 +465,9 @@ public class OpenInv extends JavaPlugin implements IOpenInv {
             return;
         }
 
+        // Replace stored player with our own version
+        this.playerCache.put(key, this.accessor.getPlayerDataManager().inject(player));
+
         if (this.inventories.containsKey(key)) {
             this.inventories.get(key).setPlayerOffline();
         }

plugin/src/main/java/com/lishid/openinv/internal/IPlayerDataManager.java

@@ -35,6 +35,14 @@ public interface IPlayerDataManager {
     @Nullable
     Player loadPlayer(@NotNull OfflinePlayer offline);
 
+    /**
+     * Creates a new Player from an existing one that will function slightly better offline.
+     *
+     * @return the Player
+     */
+    @NotNull
+    Player inject(@NotNull Player player);
+
     /**
      * Opens an ISpecialInventory for a Player.
      *