Scoped modules

Partly a proof-of-concept of scoped modules in the couchapp registry for the purposes of dogfooding/bootstrapping, but more importantly, updates to the vdu so that users don't accidentally *depend on* scoped modules from existing global packages.

Review at your liesure: @seldo @othiym23 @iarna 
If you want to rely on scoped modules, you have to scope your module.

We need to remain this way until npm@1.4 is no longer a thing we care about.