Support hoisting to nearest host.

[nathanhammond]

ember-browserify currently does a one-level deep check in an attempt to find the host application, making it work in addons which directly descend from the host. This is incomplete. Addons can be nested infinitely deep and we need to recurse up to the host.

This code is extracted from Ember CLI.

Except for the one line added by ember-engines since the host is not always guaranteed to be the top level application. The host may also be the closest lazily-loaded engine.

This code is identical to the check which ember-engines uses to support importing.

Closes #92 and #93.

[asakusuma]

@nathanhammond I presume this has been tested on past and present versions of ember-cli? I noticed that your new approach is looking for the existence of different properties than before.

[nathanhammond]

app was previously either the addon or the host application. The host application always had an import method. app.app always refers to the parent in a nested addon, so we should directly use the .parent property which was introduced in 0.2.0

Related commit.

[stefanpenner]

I don't believe we want this. We need to mangle input names, and be sure we don't collide.

[stefanpenner]

@nathanhammond spoke about it, and we have come up with a solution. Going to pair on it.

[stefanpenner]

#100 is our WIP