Transforming Ember-cpm in an standard ember addon

Still a few details to polish, but almost done.

Although ember-cpm was already an ember-addon, it was structured it with broccoli and testem before ember-cli had support for addons, so everything was a bit taylor made a not very ember-ish (as we understood it now)

I really think that familiarity is an asset for the community, so I though that we we should that stick as much as possible to the defaults in the community.

This meant:

* Use ember-cli as build/dev/test tool.
* Stick to standard jshint rules.
* Use QUnit for testing (tests are now modular and use the resolver).

It was pretty straightforward, so the only breaking changes are:
* EmberCPM no longer exposes `_utils` (which is fine, it never was intended to be public)
* I've structured all macros to be under `/macros` folder. That this makes more sense because it matches the public API (`EmberCPM.Macros.concat`). But this means that people requiring macros one by one like this `import concat from "ember-cpm/concat"` will need to change to  `import concant from "ember-cpm/macros/concat"`, so is mandatory to bump the 2nd digit of the version number.