message: Move receiver to encodings and add getters
diff: @@ -147,6 +147,7 @@ class IncomingStreamTrack
  const encoding = {
  id : id,
  source : source,
  + receiver : receiver,
  depacketizer : new Native.RTPIncomingMediaStreamDepacketizer(source)
  };
  @@ -474,6 +475,37 @@ class IncomingStreamTrack
  return this;
  }
  + /**
  + * Get all track encodings
  + * Internal use, you'd beter know what you are doing before calling this method
  + * @returns {Array<Object>} - encodings
  + **/
  + getEncodings()
  + {
  + return Array.from(this.encodings.values());
  + }
  +
  + /**
  + * Get encoding by id
  + * Internal use, you'd beter know what you are doing before calling this method
  + * @param {String} encodingId - encoding Id,
  + * @returns {Object} - encoding
  + **/
  + getEncoding(encodingId)
  + {
  + return this.encodings.get(encodingId);
  + }
  +
  + /**
  + * Get default encoding
  + * Internal use, you'd beter know what you are doing before calling this method
  + * @returns {Object} - encoding
  + **/
  + getDefaultEncoding()
  + {
  + return this.encodings.values().next().value;
  + }
  +
  /**
  * Signal that this track has been attached.
  * Internal use, you'd beter know what you are doing before calling this method
  