SDK / exoplayer

- Added support for ID3 frames of types GEOB and PRIV.

 - GEOB type is commonly used by dynamic ads provider to include in the
stream information about the ads to be played.
 - PRIV type is commonly used for time synchronization (example:
synchronizing playback of a live stream and its webvtt captions) and
also by analytics companies to include tracking information in the
stream.

- Added a sample stream from Apple that contains ID3 metadata.