couchbase-cli docs need more info and updating

From this page and its children: http://www.couchbase.com/docs/couchbase-manual-1.8/couchbase-admin-cmdline-couchbase-cli.html

I haven't gone through all of it (someone should), but the "Initializing a node" section is a bit incomplete and actually incorrect. The information contained there is for initializing the cluster, and there's no information on setting the node's data path (--node-init-data-path=PATH).

If we could go through this whole section and add more context, examples, and especially info on what commands need to be run for the first initialization, which commands need to be run on each node or are cluster-wide, etc.