Code review comment for lp://qastaging/~mhr3/dee/more-props

Ok, most of these should be fixed, (minus the writable prop on ProxyModel), I'm still unsure about constructors taking the access_mode - do we want to leave this up to apps to call g_object_new with all the props themselves, or are we going for a new constructor (I really don't like that idea if it's supposed to do the initial Clone as well).

We already have quite a few of the constructor variants, do we really want dee_shared_model_new_for_peer_with_backend_accessed_as(Peer, Model, AccessMode)?
Drop the peer? - then there's no simple way to use it with DeeClient/Server
Drop the model? - that probably makes sense if we're doing initial Clone anyway, then again DeeServer can't do initial Clone

Or perhaps just do a static method that will try to do the initial clone, and leave the constructors alone? Sounds most sane to me.