[WIP] Upgrade project to newer Ember

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This upgrades the addon to use Ember 1.12 and to use HTMLBars.
The reason I started this is because since 1.12 Ember warns about when style attributes are not set with a safe string. Which makes my application crawl to a halt in development.

This has a major breaking change: it now only works with views and components their properties, not those of controllers, which isn't a really big deal I think.

HTMLBars doesn't work well with whitespace in the output of the helper, so I removed the outputted whitespace, my guess is that glimmer fixes this.

The test suite fails on 1.13-beta and up, so that also needs to be fixed.

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So 1.13 breaks because what I presume are Glimmer introduced bugs.
The view passed in the helper isn't the correct view. So there is no way to get the target view without breaking the api.