Packet level statistics

[andrm]

• Refactoring opus analyzing to OpusAudioData, so it is available at the packet level.
• Adding finer control of writing the granule position in an Opus file.

[Gagravarr]

Thanks for all this. I've now merged it, with a few changes. Main thing is I didn't see the reason for putting the frame/sample/granule data onto OpusPacket, only OpusAudioData, and I called the getters getNumberOfSamples and getNumberOfFrames to better match the naming pattern elsewhere

Happy to revisit those changes if needed, just let me know the reasoning if you need them as here!

[andrm]

They are all fine, thanks!