Congestion control is incomplete

[jech]

Google Congestion Control (GCC) consists of the combination of two controllers: a loss-based one in the sender, and one delay-based in the receiver. Galène implements both controllers for server->client streams, but only the loss-based controller for client->server streams. Fixing that would allow us to increase the default video quality (in the absence of congestion).

GCC is described in https://tools.ietf.org/html/draft-ietf-rmcat-gcc