Command autoloading feature

This PR actually mix with 3 stuffs.

  - Command autoloading feature
  - A bug fix when throwing an ExecuteMethodNotDefinedException
  - make ProgramName of an Application be its sufficient part of $argv[0] only

I can re-organize it if you want.
Changing the prototype to this below?

```php
 protected function translateClassFilesToCommands(array $classFiles)
```