Remove download button from emberjs integration

[jasonmit]

The download button on emberjs integration doesn't apply to ember-intl. You would never, in normal circumstances, download the static assets since the addons should be installed using ember install:addon ember-intl or npm install --save ember-intl

I'd prefer we just target ember-cli with the exception of the custom packaging reserved mainly for this site.

Thoughts @ericf

[ericf]

Yeah makes sense.