Create assets pipeline for deployments

- Add new dependencies; grunt-s3, grunt-filerev, grunt-filerev-assets,
  grunt-contrib-uglify
- Rev files automatically for better cache busting when testing
- Add asset helper and use for css/js references in layout
- Add s3 upload process, configuration support and grunt task
- Restructure less files to reduce number of built files
Merge pull request #8 from jgable/assetsPipeline

Create assets pipeline for deployments