Do not add any attribute such as content, label or rtpmap if a stream is
inactive If the offerer doesn't put down a content of the main stream when the call is in a conference, then append the main stream instead of searching for the best one in the offer as this search might hit a participant stream Improve layout deduction logic: if the client SDP has no stream with main content but at least one recvonly stream without mlabel, then guess the client layout to be Grid Rework thumbnail stream index search by looking only at the client SDP Add function that verify conference info deletion on the server