Js improvements

Fixes #281 and fixes #273

- Adds fastclick
- Move customer js to the bottom of the page
- Move comment hash JS helpers to Timber's `shop.js`
- Move login/recover password JS to Timber's `shop.js`

Demo shop for new updates - http://steve-dev.myshopify.com/

@stevebosworth @mpiotrowicz 
I'd consider re-naming this to be `timber.pageSpecific` or something similar, or creating a new global called `templateVars` and having timber check for that? None of these solutions are particularly great tbh. There's no way for you to set a liquid var here that's evaluated at the bottom of the page where timber can be called directly?