Google analytics stored in js file

Currently the GA code is stored in an HTML file. GA is JS, so the file has been renamed from `frontend/app/views/spree/shared/_google_analytics.html.erb` to `frontend/app/views/spree/shared/_google_analytics.js.erb`.

I've also moved the render tag form the bottom of the page to the top to provide better analytics for GA. The .js file should allow for better syntax highlighting. Also, the if statement wrapping around the partial was moved to wrap around the render. No reason to call `render` if there is no reason to load the file up.

Comments for GA are now back to be aligned, this time horizontally.

Since Spree 2.3s support for multiple storefronts (or at least to provide some support), we have been using helper methods to grab the current store. I'm noticing that `Spree:Tracker.current` was not added to the helper methods.