feat/added Events to player

[Manuel-Barrabino]

The Player extends EventTarget in order to dispatch events to be listen with addEventListener. Those events are:

• loadeddata: Fired when the first frame of the media has finished loading.
• play: Triggered when the video starts playing.
• pause: Triggered when the video playback is paused.
• catalogupdated: Triggered when the catalog is updated. In this case, only when it's received initially.
• volumechange: Triggered when the user adjusts the volume.
• loadedmetadata:  Triggered when the video metadata (duration, dimensions, etc.) has been loaded. In this case the only metadata is when the catalog is received initially.
• error: Triggered when an error occurs during video playback.

Could not implement the next events:

• waiting: Fired when playback has stopped because of a temporary lack of data.
  We did not implement this event because it did not made sense in live edge for us.
• ended: Triggered when the video reaches the end. 
  In the current player status, it only streams nonstop.
• (nonstandard) adaptation: Triggered when the player changes the rendered video or audio track. 
  AdaptationEvents are not fired for manual track selections, so this event has no use in the current player state.
• fullscreenchange: Triggered when the user enters or exits fullscreen mode.
  This functionality is not implemented yet.
• timeupdate: Triggered periodically as the video plays, providing the current playback time.
  There is no current playback time in the player right now.