changegroup3: move treemanifest support into _unpackmanifests() By putting the treemanifest code in _unpackmanifests(), _addchangegroupfiles() will only be about files again, and we get a nice symmetry between _packmanifests() and _unpackmanifest(). The immediate benefit to me is that remotefilelog should not need to be updated to work with treemanifests. It should also make server.validate and progress output easier to get right. Probably bundlerepo too.