Use Google’s CDN for angular-mocks.js

This means we don’t have to download angular-mocks.js anymore.
Remove execSync dev dependency
Add Travis badge to README.md
Add Grunt as a dev dependency
Add basic Gruntfile.js
Add grunt-karma as a dev dependency
Add Grunt task ‘test’
Add grunt-contrib-uglify as a dev dependency
Add Grunt task ‘build’
Add grunt-contrib-cssmin as a dev dependency
Add cssmin to Grunt task ‘build’
Set ‘build’ as the default Grunt task