Proposal: Initial namespaces proposal

This is based on feedback and discussion that came out of #1017 

There was discussion that the term project may be problematic, so have removed it in favor of namespace.

I think this aligns nicely with the ACL model discussed thus far.

Feedback appreciated.

@erictune @lavalamp @smarterclayton 


Why include the namespace at all in etcd then? Just use the globally unique uuid as a key? Set up an index for namespaces with @erictune's proposed indexing thingy?