[Feature] Support ASTextNode2 Extension

[GeekTree0101]

New Feature!

Now RxCocoa-Texture support ASTextNode2 extension
Be careful use AS_ENABLE_TEXTNODE preprocessor definition (default is YES)
Usage is equal with ASTextNode :)

let textNode1 = ASTextNode2()
let disposeBag = DisposeBag()
            
Observable.just("apple")
                   .bind(to: textNode1.rx.text([:]))
                   .disposed(by: disposeBag)

[OhKanghoon]

LGTM!