feat(grunt): upgrade Gruntfile and tasks

* upgrade to latest task setup in foundermade
* add grunt-concurrent and grunt-newer for
  optimizing task runs
* refactor Gruntfile and grunt/ dir and organize
  by task type
* add google cdnify task for cdnifying libs in
  production
* update ngtemplates, usemin, injector, wiredep,
  jsHintTask, compassTask, cssWatch, jsTest,
  jsWatch, and livereload task files
* add autoprefixer, imagemin, svgmin, concurrent,
  and rev tasks for further processing and
  compressing of styles and assets, for cache
  busting in browser, and for speeding up grunt
* add src/ dir to gitignore since we expect
  usemin to mysteriously store revisioned files
  there