For control requests, we only update aspects of the broadcast if
they have changed. Therefore, if the urls list has not changed
the revid pipeline is not updated, similarly if the status has
not changed, we don't do anything there.
This change modifies vidforward to accept multiple RTMP URLs in
its control request handler. This allows for the creation of a
revid pipeline for a mac with multiple RTMP outputs.
This change adds functionality for broadcastManager state save.
This is done by marshalling the broadcastManager and saving to a
file. Loading is performed by unmarshalling an re-populating a
broadcastManager value. Testing has been added for this
functionality. Other functionality has been added a side effect.
Saxon Nelson-Milton