Add a Todos template.

This is a trivial version built with Angular and Bootstrap.
Improve upon todos template with Topcoat and FontAwesome.

Not only does this look and work better, but it's a great example
of integrating non-BACN components.
Fix the server exiting too soon.
Bubble yeoman success and failure.
Add `lb model` shim to common.
Add LoopBack model generation to Todos template.
Add LoopBack persistence to Todos template.
Fix API root for latest Workspace.