Format and minor changes of recently merged PRs

[epiclabsDASH]

• Use MAX_SAFE_INTEGER in getDuration of MPD for live streams, as suggested by @devaublanc in PR fix crash on chromecast android senders #1678 (long time on hold because CLA was not accepted). @devaublanc, thanks for the change suggestion.
• Modify PlayReady test to get licenseServerData in beforeEach.
• Set OnSeekEnd listener in BufferController just for Safari on Mac. For other browser/OS combinations there is no need to listen for this event.
• Fix getBufferLength in MediaPlayer according to documentation. Buffer Length should be NaN when there are no tracks of valid media types.
• Some format changes of previously sent PRs