debugindex: respect --debug flag to show full nodeids

localrepo.clone: add a way to override server preferuncompressed Without this patch, if the server sets preferuncompressed, there's no way for clients to override that and force a non-streaming clone. With this patch, we extend the meaning of --pull to also override preferuncompressed and force a non-streaming clone.

hg.clone: set 'stream' depending on whether --pull was requested or not In an upcoming patch we'll differentiate between the two in localrepo.