Add Notifications.showNotification() API

Signed-off-by: Jiří Janoušek <janousek.jiri@gmail.com>
Connect to init-web-worker to do initialization

Signed-off-by: Jiří Janoušek <janousek.jiri@gmail.com>
Add Nuvola.objectDiff() function

Compares own properties of two objects

Signed-off-by: Jiří Janoušek <janousek.jiri@gmail.com>
Redesign Nuvola.Player API

We have following methods instead of update():

 -  setTrack
 -  setPlaybackState
 -  setCanGoNext
 -  setCanGoPrev
 -  setCanPlay
 -  setCanPause

This is closer to Unity.MediaPlayer API

Signed-off-by: Jiří Janoušek <janousek.jiri@gmail.com>