message: get peer constraints dynamic
diff: import {IConnection} from './ConnectionInterface'
  -import JingleController from '../JingleController'
  import Account from '../Account'
  import * as JSM from 'jingle'
  -// import * as RTC from 'webrtc-adapter'
  +import * as RTC from 'webrtc-adapter'
  // import GUM from 'getusermedia'
  // import GSM from 'getscreenmedia'
  import {createRegistry} from 'jxt'
  @@ -54,13 +53,7 @@ export default class JingleHandler {
  constructor(protected account:Account, protected connection:IConnection) {
  this.manager = new JSM({
  - //@TODO this should be dynamic, see getPeerConstraints
  - peerConnectionConstraints: {
  - mandatory: {
  - 'OfferToReceiveAudio': true,
  - 'OfferToReceiveVideo': true
  - }
  - },
  + peerConnectionConstraints: this.getPeerConstraints(),
  jid: connection.getJID().full,
  selfID: connection.getJID().full
  });
  @@ -251,7 +244,7 @@ export default class JingleHandler {
  let videoWindow = new VideoDialog();
  videoWindow.addSession(session);
  - videoWindow.showCallDialog().then(() => {
  + videoWindow.showCallDialog(session).then(() => {
  session.accept();
  }).catch(() => {
  session.decline();
  