[player] Update release notes

docs/release-notes-player.txt

 Player
 ======
+1.7.0
+ - Hint and autostart functionality of videos and audios is initialized only
+   after dependencies to other audios and videos have been resolved
+ - Remove minus sign if remaining time in audio/video player is 0
+
 1.6.0
  - Include audios and videos in presentationProgress. The presentation will not be completed until all audios and videos
    with the minRun property have been played.