Merge pull request #36 from jca02266/fix-combine_latest

Correct combine_latest same as RxJS's one
Merge pull request #37 from jca02266/add-examples

Add some examples derived from RxJS observable.md
Merge pull request #35 from jca02266/fix-create

Fix Observable.create
Adding buffer/window with time
Merge remote-tracking branch 'upstream/master'