Proper Calculation of Scene Duration + Element has Infinite Band by Default

+ Add games pages to repository
+ Improve (actually, simplify) all scene duration calculations:
    * If you set duration to a scene before loading it into player (with `scene.setDuration`), then your custom duration is taken
    * You may also pass duration as a second argument to `player.load` method, even when passing `Builder` instance or `Scene` or some object with custom importer
+ All elements now have infinite band by default