Feature: Skeleton AMD Application

This PR adds:

* A "meta" infrastructure using Gulp. It's wonky, not really well-documented, but works and controls everything. Students shouldn't ever need to know about this.
    * Backend style checking (for the grunts and gulps).

* `skeleton/amd`: A working skeleton application and test suite with full infrastructure.
    * `app/index.html`: Working app page.
    * `app/js/app.js`: A self-contained mini-BB app in one file.
    * `app/js/templates/hello.hbs`: A simple template that **is** included to just let `hbs` plugin take care of everything.
    * `test/test.html`: Working test page.
    * `test/js/spec/hello.spec`: A dummy spec.

We now have some **duplicated** sources between `full/amd` and `skeleton/amd`. The Gulpfile ensures that `full/amd` can be re-run to overwrite and be "the source of truth". Ugly, but it works and makes things consistent.

/cc @colinmegill