Removed APP_PATH, switched back to use __DIR__

Using a constant APP_PATH was causing error while using "phalcon model [name]" command. I switched the template back to use magic one __DIR__ fixing the problem.

![image](https://cloud.githubusercontent.com/assets/4115643/4710632/8b98cdfa-58ac-11e4-9f82-5738f976fe6c.png)