Remove dependency on jQuery (through ember-ajax)

[initram]

It would be cool to be able to use this addon without needing to include jQuery. Also see this initiative emberjs/rfcs#386

It should be possible to use ember-fetch instead of ember-ajax

[sethwebster]

@initram Would you like to submit a working PR for this?

[initram]

I will try to make a PR for you, then we can talk about the details of it then. I may have to implement cache busting my self, but that should be a minor thing.