Ensure quotes around bound attribute values

[quaelin]

Fixes #300.

@thec0keman

/cc @jmerrifield

[thec0keman]

Thanks for submitting!

I think we need to blacklist these changes for dom events. For example, this is invalid syntax for Ember:
<select onchange=\"{{action (mut vehicle) value="target.value"}}\"></select>

This is because the action helper generates a closure that is assigned to the dom event. I'm pretty sure events would be the only dom elements that shouldn't have strings.

[quaelin]

Ok. Do you think it would work to blacklist these changes for any attribute beginning with "on"? That seems easier to maintain than an explicit list like onchange, onfocus, onblur, onmouseover....

[thec0keman]

That seems to be valid

[quaelin]

@thec0keman ok, made that change 👍

[quaelin]

Thanks for merging, @thec0keman. Any thoughts on when you might plan to publish a new version to npm?

[thec0keman]

👍