Speclate service worker

Given a offline-spec.json (generated by the speclate-cli) it generates the service worker accordingly.

Also provides a network first strategy for specs to ensure users are always seeing the latest data.

 
'use strict'
var serviceWorker = require('speclate-service-worker')
var offlineSpec = require('../offline-spec')
var version = '1.6'
 
serviceWorker(offlineSpec, version)