Support use as a `dependency` of an addon
Support use as a `dependency` of an addon

We have an internal addon which is used by a number of applications and
I wanted to be able to specify `ember-chrome-devtools` as a `dependency`
(not `devDependency`) of that addon and have the goodness that it
brings in all of our apps.

Unfortunately `ember-chrome-devtools` blows up because `this.app` is
`undefined` in that circumstance and so `this.app.env` is not
accessible.

This workaround makes things work in my use-case with one additional
gotcha. You need to explictly trigger the included hook of this addon
from your consuming addon:

```js
included: function included(app) {
  // Other stuff?
  this.addons.forEach(function(addon) {
    if (addon.name === 'ember-chrome-devtools') {
      addon.included.apply(addon, [app]);
    }
  });
},
```

There must be a better way but for now this allows me to use this
addon successfully.

dwickern/ember-chrome-devtools,dwickern/ember-chrome-devtools