Preserve timezone in formatter function

Internally, twitterFetcher.js strips the timezone from Twitter to more easily support native, cross-browser date parsing. However, this causes relative date formatting to breakdown as tweets that were published at 6PM UTC appear as if they will be published in the future when displayed at 4PM PDT.

I have added the actual datetime attribute value to the dateFormatter function arguments to support using an external library (moment.js in my case) for parsing the date and maintaining the timezone.

Please note - I did not re-minify as I'm not sure what tool you are using for that.