Fix issue #46 - Convert callback to promise syntax (#51)
Fix issue #46 - Convert callback to promise syntax (#51)

* convert callback to promise

* chain promise

* remove unused

niuyunsi/react-conf-webrtc,asinner/react-conf-webrtc,asinner/react-conf-webrtc,teamious/react-conf-webrtc,teamious/react-conf-webrtc,linweigao/react-conf-webrtc,linweigao/react-conf-webrtc,niuyunsi/react-conf-webrtc