Changes to Transloadit XHR (Mostly cosmetic)

Please review @jeresig (I intended for this to be a PR into our fork - I don't think it makes sense for their repo as they'd have to rewrite their example code as well)

Most of these changes were just aligning this file with our Khan style, as I originally had it in our codebase.

I also removed the actual calling of the functionality from the file and wrapped it in an IIFE.

I recommend reviewing with ?w=1