Serve static files first.

This means that node/express will avoid much work---e.g. looking up the user based on session id, parsing cookies, etc---if a route matches a static file. In that case, the static file is returned immediately However, it also means that static file routes will take precedence, obviously.
Wire-up client to backend user API.

The user API now supports GET and DELETE.  THe AngularJS client front-end has a service that interacts with this API.