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.
I did check whether the path is dir in the implementation code. Thus I did not assure it's a directory at beginning. We might need to further discuss about it.