The new loopback project layout adds a concept of components like
'rest server' and 'isomorphic client', each component having its own set
of boot files. The name `app.json` is confusing, since it is configuring
a component, not the app (which is the whole project).
Breaking change.
In the new 2.x project layout, definition of loopback Models is out of
scope of the boot process. The bootstrapper only configures existing
models - attaches them to a dataSource and the app object.
Move `app.boot()` and its tests from loopback.
Fix jshint warnings.
Clean up unit tests - remove dependency on global variables created
by loopback's test/support.js
Miroslav Bajtoš