Make 'childLinkViews' and Ember Array
Make 'childLinkViews' and Ember Array

Make the `childLinkViews` property an Ember Array, instead of having
the Computed Properties convert it (setup for future commits). This
commit includes a few other related changes;

* Create the initial array in the `init()` hook
* Run `_super()` on the `didRender()` hook
* Change `var` to `let` for variable declarations

gordonbisnor/ember-cli-active-link-wrapper,gordonbisnor/ember-cli-active-link-wrapper,alexspeller/ember-cli-active-link-wrapper,alexspeller/ember-cli-active-link-wrapper