test(repeat): add unsubscription tests for repeat
test(repeat): add unsubscription tests for repeat

Add tests for subscription/unsubscription moments of the repeatable
source for the repeat operator.

Resolves issue #554.

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