Add Class Naming confension and prefix

Core
	file: <Class>.php
	class: Core_<Class>

Controllers
	file: <Class>.php
	class: Controller_<Class>

Libraries
	file: <Class>.php
	class: Library_<Class>
	loaded: $this->Lib<Class>

Models
	file: <Class>.php
	class: Model<Class>.php
	loaded: $this->Model<Class>