Support for engines

[enniel]

Add support for ember-engines. With lazy loading yet not worked.

[miguelcobain]

I have moved the templates from the app to addon folder in master.
Can you rebase?

I see you're pulling dependencies from npm now. That's very desirable.
Have you considered using ember-cli-node-assets? It provides a nice abstraction on the npm import story.
Example: https://github.com/miguelcobain/ember-sticky/blob/master/index.js#L8-L17

[knownasilya]

@enniel which version of engines did you test against for lazy support?

[knownasilya]

@John0x see if you can try this PR. It works for me. Just make sure to share the -document service to your engine.

[knownasilya]

@miguelcobain this is ready I think. Seems to work with lazyloaded engines too.

[miguelcobain]

I'm just concerned that prism was removed from bower. Either ember-prism includes prism from npm or the conde highlighting stopped working in the demo app.

[John0x]

This PR works for me too, would be great to see it being merged.

[miguelcobain]

Thanks to the missing in action @enniel for starting this. :D
Thanks to @knownasilya @John0x and @mellatone for helping to test this.
This was merged and released. Have fun.