Feature/js analytics

@benbarnett 
@aduggin 
@andrewgarner 

I have added analytics, this uses requirejs to load application.js, inside application requirejs config is set, mas_analytics is loaded, and a demo is called which runs on home page.

I have also moved the fontloading into the application.js, this is cleaner, should have little implact on load as it is the first thing I call, but as it is after requirejs loads application.js the concurrent loading of JS may be noticeable on mobile, worth testing. We would need to test time to render on different speed+latency connections.

Questions which may need addressing before pull
  1. should bower modules be commited, or in an ignore file and everyone install locally
  2. no tests written yet, will probably need to pair with @andrewgarner to write the first one
  3. the example is a dummy written to work on the home page and will need to be changed for article page once merged, the exact implementation of this may change when we add more pages requiring tracking, but I dont want to over optimise at this stage until requirements become more clear.
  4. require could be loaded as a gem, this may give us some useful functionality when optimising, but it feels cleaner to use bower for all frontend/js - @andrewgarner might want to have a look at https://github.com/jwhitley/requirejs-rails , again we can optimise later when it becomes useful/necessary