added InventoryCommand to CommandListener to call inventory in game

src/main/java/org/bitbiome/commands/CommandListener.java

@@ -18,6 +18,8 @@ public class CommandListener {
         commands.put("quit", new QuitCommand());
         commands.put("location", new LocationCommand());
         commands.put("travel", new TravelCommand());
+        commands.put("inventory", new InventoryCommand());
+
     }
 
     public HashMap<String, CommandAPI> returnCommands() {