test(ScalarObservable): add test cases for thisArg
test(ScalarObservable): add test cases for thisArg

Closes #996.

RxJS-CN/RxJS-Docs-CN,figueredo/RxJS,justinwoo/RxJS,SangKa/RxJS-Docs-CN,adrianomelo/RxJS-1,RxJS-CN/RxJS-Docs-CN,martinsik/rxjs,Igorbek/rxjs5,ReactiveX/rxjs,jayphelps/rxjs,ReactiveX/rxjs,elliotschi/rxjs,elliotschi/rxjs,robwormald/RxJS,justinwoo/RxJS,robwormald/RxJS,elliotschi/rxjs,Brocco/RxJS,SangKa/RxJS-Docs-CN,jinroh/RxJS,martinsik/rxjs,SangKa/RxJS-Docs-CN,ReactiveX/RxJS,martinsik/rxjs,ReactiveX/RxJS,elliotschi/rxjs,IgorMinar/RxJS,jayphelps/rxjs,jinroh/RxJS,robwormald/RxJS,Igorbek/rxjs5,ReactiveX/RxJS,figueredo/RxJS,adrianomelo/RxJSNext,staltz/RxJSNext,figueredo/RxJS,figueredo/RxJS,gluck/RxJS,kwonoj/RxJS,Brocco/RxJS,staltz/RxJSNext,adrianomelo/RxJS-1,robwormald/RxJS,jinroh/RxJS,Igorbek/rxjs5,jinroh/RxJS,jadbox/RxJS,trxcllnt/RxJS,adrianomelo/RxJS-1,Brocco/RxJS,jadbox/RxJS,saneyuki/RxJS,ReactiveX/rxjs,jayphelps/rxjs,kwonoj/RxJS,jadbox/RxJS,ReactiveX/RxJS,benlesh/RxJS,staltz/RxJSNext,benlesh/RxJS,IgorMinar/RxJS,ReactiveX/rxjs,jayphelps/rxjs,martinsik/rxjs,jadbox/RxJS,justinwoo/RxJS,Igorbek/rxjs5,SangKa/RxJS-Docs-CN,adrianomelo/RxJSNext,jayphelps/rxjs,gluck/RxJS,adrianomelo/RxJSNext,benlesh/RxJS,gluck/RxJS,trxcllnt/RxJS,staltz/RxJSNext,kwonoj/RxJS,RxJS-CN/RxJS-Docs-CN,benlesh/RxJS,justinwoo/RxJS,adrianomelo/RxJSNext,trxcllnt/RxJS,trxcllnt/RxJS,RxJS-CN/RxJS-Docs-CN,saneyuki/RxJS,kwonoj/RxJS,adrianomelo/RxJS-1,gluck/RxJS,Brocco/RxJS