Add explanation of the behavior for multi-party codec negotiation
Add explanation of the behavior for multi-party codec negotiation

tieto/farstream,tieto/farstream,shadeslayer/farstream,shadeslayer/farstream,tieto/farstream,kakaroto/farstream,tieto/farstream,pexip/farstream,kakaroto/farstream,pexip/farstream,pexip/farstream,kakaroto/farstream,shadeslayer/farstream,tieto/farstream,ahmedammar/skype_farsight2,ahmedammar/skype_farsight2,shadeslayer/farstream,ahmedammar/skype_farsight2,ahmedammar/skype_farsight2,pexip/farstream,kakaroto/farstream