Updated how we declare variables

Per @bdoms suggestion of being explicit on variable declarations. 

Article @bdoms referenced: http://benalman.com/news/2012/05/multiple-var-statements-javascript/

I also had the ingenious idea of pushing this to airBnB (by accident), and we got some nice feedback from a couple of their engineers as well: https://github.com/airbnb/javascript/pull/143

@doomspork @GabKlein @amdtech @jmacadam @jcarouth feel free to debate if you want. I am neutral on this one.