Refactor all code base on #1

* Remove `new` operator for new class definition. Change to directly function invoking.
* Combine single class definition and extend definition.
* Remove `__super__` keyword. Because it may confuse user when using `this.__super__.xxx` to invoke method from 2 or more layer upper.
* Change static inheritance by default but not override.
* Update `README.md` and do some typo fix.